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Let's do this.
>>
50%
>>
25%
>>
Anyone who thinks the answer is 50%, please kill yourselves.

You are completely useless and will bring nothing of value to the human race.

The answer is 1/3.
>>
>>700654414
1/3
bayes rule and such
give me something hard, anon
>>
>>700654414
If you've ever taken Statistics and have basic reading comprehension, it's 50%.
The phrase "given that at least one of them landed on heads" limits us to always have 1 head, the percentage is based on the second coin which still has a 50% chance to land on land no matter which of the two coins that isn't guaranteed to be heads
>>
>>700654742
I eat dicks, listen to them
>>700654660
>>700654601
>>
>>700654414

> given that at least one of them landed heads.

Thats irrelevant.

Or they both land heads or only one land head or the other land head or both land tails

answer is 25%

Pissers.
>>
The answer's 1/3 and if you didn't write this you're a moronic fucking faggot
>>
>>700654414
12.5%
>>
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>>700654845
>>700654570

Kill yourselves
>>
1 in 3
Heads heads
Heads tails
Tails tails
>>
>>700654742
Correct!! hense why i was first to say 50% good to know there's some intelligence left on /b/
>>
>>700654601
says the nigga who works in Walmart
>>
>>700654414
50%.
Two coins, one is already heads, thus already out of the equation.
One coin, heads or tails.
>>
>>700655061
>given that at least one of them landed heads
>tails tails

>landed heads
>tails tails


u dun goofd anon
>>
>>700654601
>>700654660
>>700654865
>>700655061
b8/3
>>
>>700654414
It's now the probability of one coin being heads. 50%

>>700654660
No, not fucking bayes (go eat a dick)
>>
>>700655117

Which coin?

Answer is 1/3
>>
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>>700654511
>>700654570
>>700654845
>>700654892
>>700655065
>>700655117
>>700655225

Actual fucking retards
>>
Its a play on words you dumb cunts
>>
It's obviously 50%
>>
>>700655294
The one that landed heads. One coin always lands heads, and one coin has the choice of landing heads or tails.
1/2.
>>
>>700655225

You're retarded. Congratularions.

Answer is 1/3, plebs.
>>
>>700655328

It's a basic conditional probability question, you dumb cunt.
>>
the people giving answers other than 50% will post in IQ threads claiming theirs is 138

oh /b/.
>>
>>700654660
Are you a fucking retard?

Look at Bayes' formula and you'll see it's actually fucking 50%
>>
>>700655400
>One coin always lands heads

You're an idiot.
>>
>>700655579
>[...] given that at least one of them landed heads?
>>
>>700655521
>>700655476
>>700655310
>>700655294
>>700655061
>>700654892
>>700654865
>>700654845
>>700654660
>>700654601
>>700654570

are you all trolling or completely autistic?

you're basically saying a single coin as 1/3 of a chance to land on heads.

>guaranteed heads on the other coin
>>
>>700654742
>>700655065
>>700655117

Wrong, this would only be true, if both coins would be flipped after each other, and if we were looking at the propability of 2 heads after the first toss has resulted in a head.

What the text actualy asks for is the propability for 2 heads, if atleast 1 head is present after BOTH have been tossed, and for some reason you know that one is head, but not what the other one is.

Thus we can caluculate it as

(Propability of 2 heads) over (Sum of Probabilty of all combinations that contain 1 head)

this is true because the alternative of "no heads" has been eliminated by us knowing that atleast one head has been seen.

now the combinations

heads tails
tails heads
tails tails
heads heads

are a-priori all equally as probable, with a chance of 1/4 each.

inserting this into bayes rule as mentioned before we get:

(1/4)/(1/4+1/4+1/4)=(1/4)/(3/4)=1/3
>>
These are the combinations that can result from flipping two coins:

HH
HT
TH
TT

TT can be eliminated, because we know that at least one coin is heads:

HH
HT
TH

Out of those 3 possibilities, 1 has both coins landing heads.

The probability is thus 1 out of 3, or 1/3.
>>
>>700654414
I think this is a question of interpretation of the question. You can look at it in two ways:

"One coin landed heads. What is the probability that the other one lands heads as well?" -> in that case the probability is 50%, because the first coin doesn't influence the second one.


The other way you could understand this question is akin to the monty hall problem.
Let's say that 2 coins were flipped. The possibilities are:
TT, TH, HT, HH

That's 1/4 per possibility, so normally there's a 25% chance that the coins will land HH. So if someone flipped two coins, you'd have a 25% chance that you'd be right if you guessed HH.

However if someone flips two coins and then tells you that one of them landed H, the possibilities are now:

HT, TH, HH

Obviously the TT possibility was eliminated because you know that at least one coin landed H. So now you're basically guessing which of the options HH, TH, HT the coins landed. That's 1/3 per option, so a ~33% possibility.


There. Now OP can go fuck himself with his bait
>>
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Wrong, faggot. It's like you can't read or something.

Two regular coins WERE FLIPPED. Past tense. It happened already.

>but it says that one.....

but-but-but-but-but-buh-buh-b-b-b-b-

NO!. LISTEN, you stuttering imbecilic fuck; When you flip TWO REGULAR FUCKING COINS, there are 4 (count them, 4) EQUALLY PROBABLE outcomes possible. These are as follows (probabilities in brackets):

HH (1/4)
HT (1/4)
TH (1/4)
TT (1/4)

Now, the question is a CONDITIONAL probability question. It specifies a condition. The condition is that AT LEAST ONE COIN LANDED HEADS. Note: NOT to be confused with "One coin WILL land heads" or "One coin ALWAYS lands heads" Or "One coin is GUARANTEED to land Heads." No. None of those are true based on the question. The question simply tells us that at last one coin landed heads. It doesn't say which coin it is or give us any other information about the flip.

So, we have to look back up there to our list of outcomes and count how many of them satisfy the condition of having AT LEAST ONE HEADS coin: Weel, let's look at what we get:

HH
HT
TH

WOW, look at that. 3 equally probable outcomes which ALL satisfy the condition. This means that the result could be ANY of these 3 outcomes.

Now, we next need to see how many of those 3 outcomes contains two heads coins. Well, look at that:

HH

So, 1 out of 3 equally probable outcomes contains both heads.

1/3

If you do not understand after this, just kill yourself, or at least never have children.
>>
1 in 2. Same as anything in the universe. It will or it won't happen. No amount of known variables in all of existence will ever make that statement false.
>>
>>700655779
>>700655826
>>700655841
>>700655866

this
>>
>>700655779
Thank you
>>
1/3
why?
lets list all cases
TT this flip is invalid since non landed heads
TH
HT this is different from TH because we have two different coins
HH this is what we are looking for
-> 1/3
>>
>>700655696
>you're basically saying a single coin as 1/3 of a chance to land on heads.

No, we're not you stupid cunt. We're saying that the probability of both coins being heads when AT LEAST ONE coin landed heads is 1/3, which is correct.
>>
its obviously 1/4
2 coins, 2 possibilities each
/thread
>>
You are all missing something, read the fucking question you degenerate cunts.

>The condition is that AT LEAST ONE COIN LANDED HEADS. Note: NOT to be confused with "One coin WILL land heads"

are you actually retarded?

i can't deal with this autism
>>
Yeah, I can deal with being wrong.
What're your stances on gold and silver balls in boxes?
>>
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>>700655779
Kek. If this not bait you are retarded
>>
http://www.braingle.com/brainteasers/teaser.php?op=2&id=29228&comm=0
>>
>>700656002
you're not tho. one coin is already guaranteed to land on heads, therefore the probability of the other coin landing on heads is 50%

kill yourself
>>
>>700655779
But tails tails never happens
>>
>>700656199
Hey retard one Lands heads 100%.
Ur possibilities are only heads heads, noheads heads, heads noheads.
>>
>>700656323
exactly, because 0/(3/4) is still 0

0 obviously beeing the propabilty that the result will be tails tails after it is know that one toss resultet in heads.
>>
>>700655866
this guy is the kind of nigga to sit at parties (when he gets invited) and try to chat up the landwhales using math

>only to still be rejected
>>
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>>700656199
>one coin is already guaranteed to land on heads
>gauranteed to
>in the future

Are you fucking retarded? The flip already happened, and at least 1 of teh 2 coins landed heads.

>ALREADY landed

it wasn't GUARANTEED, and we don't know which coin it is.

This means that EITHER coin could be tails, just not BOTH.

That gives us 3 equally likely outcomes, all containing at least 1 heads:

Heads - Heads
Heads - Tails
Tails - Heads

1/3

>inb4 HT is the same as TH

No, morons. They are 2 distinct outcomes.

1/3
>>
>>700654511
>>700655117
>>700655225
>>700655346
>>700656199
if they were electrons you'd be right.

they're coins though.

1/3
>>
>>700656677
HT is the same as TH

one is heads, the other is tails, no matter the order of the coins

it's 50%
>>
>>700655841
I normally dont respond to these threads, but i saw this scrolling past, and its absolutely correct. The original question is framed imprecisely. The probability is different depending on whether the question is asked before the coins have flipped, or after one has flipped and landed heads.
>>
>>700655866
>>700655841
>>700655826
Ok I was wrong
>>
>>700656916
graduate highschool, faggot
>>
>>700656916

You're either trolling or completely buttfucked retarded.

Either way, you're not worth explaining the solution to.

Everyone who isn't retarded can read the solution ITT already and see the answer is 1/3

Your b8 has failed.
>>
Why are people so fucking retarded... It's obiously 50%. Fucking shit-tier education
>>
>>700654511
/thread
>>
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ok faggots we already have 2 coins

There's 2

If flipped there's a 25% chance they'll both be heads

Now if 1 stays head all the time, you have 1 coin with a head/tails 50/50 chance being heads

100% probability coin with the 50% chance coin.

So it's 50/50
>>
>>700657083
>thinks a single formula applies to every given situation

just end yourself, you mad virgin boi
>>
>>700655310
No we can clearly see who the retard in this thread is
>>
Saying it isn't 50 percent because the first flip being heads doesn't factor into it is the same as saying "Oh, flipping a normal coin and getting heads is less than a 50 percent chance, because you have to factor in the chance that coins were ever even invented!"
>>
>>700657402

not the other anon, but what the fuck are you talking about?

>>700657380
>Now if 1 stays head all the time

It doesn't.

1/3
>>
>>
>>700656677
the question isn't asking the probability of a given outcome

HH = 1/3
HT = 1/3
TH = 1/3

the question is asking whether a coin that has a 50% probability of landing heads or tails, lands heads, given one coin is guaranteed to land heads.

i don't see why you are all struggling with this so much
>>
>>700657657
>It doesn't.
Read that last fucking sentence>>700654414
>>
>>700657380
I thought that to but both coins have an equal chance of being tails. Its not just one coin allways landing heads
>>
>>700657750
>the question is asking whether a coin that has a 50% probability of landing heads or tails, lands heads, given one coin is guaranteed to land heads.
>one coin is guaranteed to land heads

CRITICAL ERROR

CRITICAL ERROR

ABORT

ABORT

No coin is guaranteed to land heads.

2 coins were already flipped, and at least 1 of them landed heads.

it could be coinA or coinB.

This gives us 3 equally likely outcomes

CoinA - BoinB
Heads - Tails
Heads - Heads
Tails - Heads

1/3
>>
>>700657769

You said
>1 stays head all the time

OP's questions says
>at least one coin landed heads

Do you not see the difference between those 2 statements?

Your statement implies that 1 coin is FIXED as heads.

OP question doe not imply any fixed coin, simply that at least 1 coin landed heads after the flip. it could be EITHER coin, meaning EITHER coin could be tails, just not both simultaneously.

So no coin is fixed in the OP question. It is in yours.

Answer to your scenario is 1/2

Answer to OP question is 1/3

Pic Related
>>
your autism has surpassed me

>one coin is guaranteed to land heads
>it could be coinA or coinB

so yes, one coin?

holy shit

the answer to this question is 50%, it's a play on words, and you nerds aren't acknowledging that. End of story.
>>
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>>700658321

Retard, there is a difference between
>one coin is guaranteed to land heads
and
>at least one coin landed heads

If you don't understand the difference, work on your reading comprehension.

Answer is 1/3

Source:
http://courses.cs.washington.edu/courses/cse312/11wi/slides/04cprob.pdf
>>
> preassumed heads and tails are the only outcomes of a coin flip
50 percent. it doesn't matter WHICH coin landed heads (=: B). the other coin can land heads or tails, thus 50 percent possibility that it lands heads.
A := "other coin lands heads"
P(A | B) = P(A n B) / P(B) = //A and B are independent
= P(A) * P(B) / P(B) = P(A) = 0.5
>>
>>700654414
The average is 37% of the time it will land opposite of what face you flipped from.
>>
Anyone who thinks it's not 50% is fucking stupid

>>700655579
You're a fucking moron, reread the problem and come back when your autism isn't so heavy
>>
If order matters then it's 1/3. If order doesn't matter then it's 1/2.
>>
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>>700658568

Incorrect.

A = "both coins are heads"
B = "at least one coin is heads"

P(A|B) = P(A∩B)/(P(B)) = (1/4)/(3/4) = 1/3
>>
>>700658778

If you think it's 50%, you're retarded.

Congratulations.

>>700658793

You're a fucking idiot.
>>
>>700654511
/thread
>>
The phrase "at leas" implies that you have to use counter probability and have to assume that bot dont land on heads, so its

1/2*1/2= 0,25

Now you have to subtract this from 1 and you get

P(E) = 0,75% for at least one to land on heads.
>>
>>700658909
You're literally autistic. If one is guaranteed to land on heads then it may as well be ruled out of the equation because the outcome is 100% heads for that one. That leaves one coin and if you think the probability of a coin landing on heads is 1/3 then you must be a fucking second grader
>>
50%
>>
>>700655779
retard confirmed
>>
>>700659096
>If one is guaranteed to land on heads

It isn't. There's your mistake.
>>
ITT: idiots who assume that the coins were only flipped once each
>>
>>700659096
One coin is not guaranteed to land on heads. One of two lands on heads
>>
>>700659261
Which one?
>>
>>700658804
wrong.
A := the other coin is heads
B := a coin is heads
A | B := "the other coin is heads GIVEN that a coin is heads"
P(B) = 50 % /= P(A)
P(A | B) = ... = P(A) = 50 % as I already wrote in the other post.
>>
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>>700655866
>>700655779
>>700654414

Get ready for me to blow your mind.

In standard mathematics, you determine the probability of multiple events occurring by multiplying the probability of each event by one another. So in the case of a coin flip. Each coin has a 50% chance of landing heads, and therefore you multiply 0.50 by 0.50 to get the result of 25%. The chance of both occurring is 25%

In this situation. Your four results (Heads/tails, tails/heads, tails/tails, and heads/heads). Have one permanently disqualified (TT). Which leaves three situations. HT/TH/HH

If you look at the right coin individually, in two of those three scenarios it can be heads.
If you look at the left coin individually, in two of those three scenarios it can be heads.

So each coin individually has a 66% Chance to land on heads. 0.66*0.66=43.56%


The system has a 43.56% chance for both coins to land on heads if T/T is disqualified.
>>
>>700659261
Fuck, now I see what you mean
>>
>>700659310
does not matter. we didn't give them numbers or another thing to divide them.
>>
>>700659359
>In standard mathematics, you determine the probability of multiple events occurring by multiplying the probability of each event by one another.
wrong, retard
>>
>>700659403
then how do you know it landed heads?
>>
Damn, you niggers are dumb.

This is a conditional probability question.

In simple words, it is asking what is the probability of event A given event B.

To answer a conditional probability question, we use Bayes' theorem.

Which in simple words looks liek this

(Probability of event A) DIVIDED BY (Probability of event B)

Event A = 'Both Heads' = 1/4
Event B = 'At least 1 Heads' = 3/4

So the probability of event A GIVEN event B is
1/4 DIVIDED BY 3/4
and that equals 1/3

1/3 is the answer.
>>
>>700655696
Don't be absurd. Someone who is autistic would know it's 50%.
>>
>>700654414
Step one: H or T
Step Two: Depending on the H or T, HT, HH, TT or TH. We want HH, since we want both to land head, and the first one did.

HH is one possibility out of four. To get HH, we have a 25% probability.
>>
>>700659546
>(Probability of event A) DIVIDED BY (Probability of event B)
wrong, fucker
if you're going to shout HURR DURR BAYES, you'd better know what Bayes Theorem is.
>>
>>700659359

Holy shit, you're retarded.
>>
>>700659704

You've never heard of bayes' theorem before have you?
>>
>>700659359
>>700659436
>>700659711

I keep rereading what he wrote but it makes complete sense. could someone elaborate on what's wrong?
>>
Did anyone get the right answer yet?
>>
>>700659628
>since we want both to land head, and the first one did.
>the first one did

Incorrect
>>
>>700659840
Here's a tip, you little shit sucker: P(A and B)
>>
>>700659074
The question states at least one lands on heads, and your reply is that there's a 75% that at least one lands on heads?

Are you retarded?
>>
>>700659891
That's for independent events.
>>
>>700659964
Proof me wrong
>>
>>700659840
please tell me more about Bayes Theorem
can you write it correctly this time?
>>
>>700654601
see:
>>700654742
>>700654742
>>700654742
>>
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>>700659891
>So each coin individually has a 66% Chance to land on heads. 0.66*0.66=43.56%

That.

2 regular coins were flipped. there are 4 equally likely outcomes for a 2 coin flip. These are:

HH (1/4)
HT (1/4)
TH (1/4)
TT (1/4)

The question specifies a condition. the condition is that at least one coin landed heads. This eliminates the TT outcome only, leaving 3 equally likely outcomes.

3 equally likely outcomes.

HH
HT
TH

1 of those 3 is HH

1 of 3

1/3

Do I need to draw a Venn Diagram now?
>>
>>700659902

Yes.

1/3

See Washington University
Source: Slide 4
http://courses.cs.washington.edu/courses/cse312/11wi/slides/04cprob.pdf
>>
>>700660227
How'd you figure out that the coins were only flipped once? I don't see that in the question.
>>
>>700654414
>>700659359

This anon is kinda right
If we treat the two coins as a system. Its 33% (1/3rd)

If we treat the two coins as a system but disqualify the failure state (TT), then look at individually the probability each coin has of landing heads. its 43%

If we treat the coins as a non-system and ignore one of the coins because its results no longer matter ,and that coin will always have to be heads because of the rules. Its 50% (1/2)


>>700660227
See above.
>>
>>700660303
That seems to assume that each coin is flipped once, so it's a different question than OP's. It's a good start, though.
>>
>>700654414
50/50
One is already heads.
>>
>>700660227
the question, idiot, was what the probability of the second coin landing heads is. that is 50%.

IT IS COMPLETELY UNAFFECTED BY THE FIRST COIN. DO YOU UNDERSTAND THE FIRST COIN WILL ALWAYS BE HEADS BECAUSE THE QUESTION SAYS IT IS HEADS. YOU MUST IGNORE FIRST COIN.
>>
>>700660441
>50/50
100%
amazing!
>>
>>700659953

P(A and B) = 1/4 (Both heads AND At least 1 heads)

P(B) = 3/4 (At least one heads)

P(A and B) / P(B) = (1/4) / (3/4) = 1/3

1/3
>>
>>700660450
It never says that it's the first coins that guaranteed to land heads.
>>
>>700660366
/thread
>>
>>700660640
It never says to flip each coin once, either.
>>
>>700655779
Math major here (not that anyone would care or believe me)
This is a good explanation. For anyone doubting it, there is a reason why no one has been able to point out a flaw in the reasoning here.

Although I did think this one was pretty funny even though obviously intentionally wrong
>>700659359
For anyone on the verge of believing - he goes from saying there is 50% chance of heads do 66% chance of heads - clearly not consistent.

Re everyone saying 50%, you are wrong and you can test empirically if you can be bothered by flipping 2 coins like 100 times. Every time it is double heads, note it down in column a. Every time it's mixed, note it down in column b. Every times its double tails, don't note anything down. The more you do it, the closer you will get to the right answer.
>>
>>700660450
>what the probability of the second coin landing heads is

That's not the question, you fucking moron. you are assuming that the FIRST coin flipped landed heads. you cannot know this.

The question is
>What is the probability that both coins landed heads given that at least one coin landed heads?

The answer to that question is 1/3
>>
>>700659310
Either or both
>>
>>700654414
50%
the second coin doesn't know the result of the first, so the chance is exactly 50% to land either side.
see gamblers fallacy for explanation

25% would be if you did not know the first result, i.e. throw both coins after the question, simultaneously.

any other percentage is just plain wrong.
>>
>>700660366
>This anon is kinda right

He's completely incorrect.
>>
>>700660744
>no one has been able to point out a flaw in the reasoning here
assumes each coin is flipped only once
>>
itt: stupidiots trolling neckbeards, like with that math shit with ellipses and whatnot, hurr this is no division sign durr.

it's 50%
>>
>>700654414
TT = 50% * 0% = 0%
TH = 50% * 100% = 50%
HT = 50% * 50% = 25%
HH = 50% * 50% = 25%
>>
For all of your saying the probability is 1/3, this is your logic:

3 possibilities:
{H,H}
{H,T}
{T,H}

Do you realize it doesn't matter which side the heads coin is on? Nothing about this says consecutive; {H,T} is the same as {T,H}, please kill yourself if you don't know it's 50%
>>
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>>700660744
>you can test empirically if you can be bothered by flipping 2 coins like 100 times.

Or you could just write a simulation.

Answer is 1/3

Pic Related
>>
>>700661032
this
/thread
>>
>>700659436
It's actually not wrong. If you're calculating the chances of something happening twice in a row you do it like that. If the probability of something happening is 1/3 then happening twice is 1/3 * 1/3. Which is 1/9.
>>
>>700660784

OP's question is a conditional probability question. It does not say the first coin landed heads.

The answer is 1/3.

1/3 does not contradict teh gamber's fallacy rule.
>>
>>700661045
>programming wrong
>math weird
"see, i'm right!"

fuck off.
>>
Did any of you even read the question?
>>
>>700661032
He right u no
>>
>>700661146
That's the definition of independent events. You can't assume that holds for arbitrary events.

HAND, please retake STAT 101
>>
>>700661045
A simulation doesn't matter if you don't understand statistics in the first place

see
>>700661032
>>
>>700661032
>{H,T} is the same as {T,H},

No it isn't you simpleton. Allow me to educate you.

Take two different coins. Let's say, a penny, and a quarter. Each coin has a 50% chance of landing either heads or tails. You flip both coins. What are the possible outcomes? Well, let's see:

penny = heads & quarter = heads
penny = heads & quarter = tails
penny = tails & quarter = heads
penny = tails & quarter = tails

4 possible outcomes. Each of them equally likely to occur (25% or 1/4)

Now, surely we can all see how the results,
penny = heads & quarter = tails
and
penny = tails & quarter = heads
are different, right? Surely you can see how these are two distinct, separate and equally probable outcomes, yes?

Great, let's continue. Now, it DOES NOT MATTER if you are using two identical coins. HT & TH are two distinct results, and the probability of at least one of them occuring is TWICE the probability of a HH or TT outcome. Remember HT(1/4) + TH(1/4) = 1/2.

So, since we know that TT can't be the result in the OP question, it is discarded, and we are left with the possible outcomes:

HH (1/4)
HT (1/4)
TH (1/4)

Three equally probable outcomes containing at least one heads, hence the answer = 1/3
>>
>>700661250
Actually, you can. learn2math man.
>>
>>700660784
Their flipped at the same time
>>
>>700661289

If you think HT is the same as TH and not 2 separate and distinct outcomes, then you are retarded.

If you want to think of HT and TH as the same, then you must add their probabilities together, giving you

HH = 1/3
HT/TH = 1/3 + 1/3 = 2/3

1/3

Read this >>700661294
>>
>>700661294
You're obviously one of the tards who don't understand the question. We're not flipping two coins from scratch and just eliminating the result if they're both tails. The questions sets up the scenario where 1 coin is heads, regardless of which one
>>
>>700660227

>3 equally likely outcomes.
>HH
>HT
>TH

But the left coin has a 66% Chance of being heads
And the right coin has a 66% Chance of being heads

Which doesn't add up to 1/3rd. Your mistake is not realizing the coins DONT have to be connected to one another. There's actually more than 3 results.

The Coin on the left can land on
H
H
T

The Coin on the Right can land on
H
T
H


Which means the possibilities would be
HH
HT

HH
HT

TH
TT <Disqualified

Putting the chance of getting heads somewhere around 40%
>>
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>>700655203
kill yourself
>>
>>700661376
fine, I'll teach you

3 marbles in a jar
1 white
2 black
draw 1
probability of drawing a black marble: 2/3
probability of drawing a white marble: 1/3
probability of drawing a white marble and drawing a black marble: 0 or 2/9 ?
>>
>>700654414
I know technically it should be 1/3, but logically...

You flip two coins into two separate boxes. You look in box A, Coin landed heads. Condition Met: At least one coin is heads. Now, if you're going to check box B, it can be either heads or tails.

I say this simply because they state that they're regular coins, so the only way to know at least one was heads would've been to check it before checking the other, as a regular coin can't be guaranteed heads.
>>
>>700661466
>If you want to think of HT and TH as the same, then you must add their probabilities together

What the fuck? Do you know how retardedly wrong that sentence is?
>>
>>700661805

I know how retarded you are.
>>
>>700654414
You uneducated spastics talking out your ass. over complicating it because you are fucking dumb asses talking about stuff you have no idea about, probability is the the number of possible wanted outcomes over the overall possible outcomes, so we want 2 heads, we have 2 coins with 2 heads and 2 tails, so 2/4. the first coin is decided, so now we look at the second one hoping for heads, it has a heads and a tail 1/2. the answer is 50%, and to those fucking scumlords with IQs on par with 10 year talking shit.. well they should just kill themselves honestly. such a simple problem, you small minded cunts. i fucking hate how dumb you all are, KYS!
>>
>>700654601
you are so fucking dumb KYS!
>>
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>>700654414
retards in this thread need some education
>>
>>700661682
You're even doing it wrong.

Say you pick the white one first. Then it's
1/3 * 2/2 = 2/6 chances.
>>
The question says regular, but not fair. Regular coins are biased. A fair coin would not be ordinary.

You need to use the bias of the coins to get the answer.
>>
>>700662009
>draw 1
>draw 1
>draw 1
>draw 1
>draw 1

are you blind or retarded?
choose EXACTLY ONE
NOT TWO
>>
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>>700661655
>But the left coin has a 66% Chance of being heads
>And the right coin has a 66% Chance of being heads

In what universe?

>The Coin on the left can land on
>H
>H
>T

Why are you listing H twice?

I'm not even going to bother.

Answer is 1/3

Source: Washington University
See slide 4
http://courses.cs.washington.edu/courses/cse312/11wi/slides/04cprob.pdf
>>
>>700661912
Wow you got me there, proved me wrong

Great job you get an A in deh maths
>>
>>700662108
Of course that's impossible but your argument makes no fucking sense kid. I don't know if you're bad at math, english or even both.
>>
>>700661913
>the first coin is decided

No, it isn't.

1/3
>>
>>700662009
>determine the probability of multiple events occurring by multiplying the probability of each event by one another.
You didn't multiply the probability of the two events (2/3 and 1/3), so either you were wrong before or you're wrong now.
Which one is it?
>>
>>700661655
are you retarded, anon?
You take the possible combinations and then rearange them to make more...

i hope you realise how stupid that is.
>>
>>700662325
YES IT FUCKING IS YOU RETARD READ THE QUESTION. OMG YOU MAKE MY BRAIN HURT!
>>
>>700662305
One of us has taken graduate courses in mathematics and it wasn't you. Maybe you should reflect a little more on your unwarranted self-confidence.
>>
>>700662240

I got you long before that post, broski.

It's good that you've finally admitted your mistake and now understand the correct answer of 1/3.

It shows that you're not COMPLETELY retarded.
>>
>>700662335
I actually did.
If you pick one marble out of the bag, that's the first event and leave it out. Then you pick another and that's the fucking second event. Are you this retarded? Where the fuck did you even study.
>>
>>700662428

Where does the question say the first coin is heads?
>>
>>700661695
It is a little counter-intuitive, but you are wrong. Read up on it a little. Also interesting is the dilemma with the gameshow where you can win a car or a goat. You should find a proper explanation if you google that.
>>
>>700662442
Oh, jesus mate. How can you be so dense.
>>
>>700662325
"given that one coin landed head" "landed heads" "head" "ONE COIN" are you thick or just inbred
>>
>>700654414
its 50% you guys are overcomplicating the shit out of this.

1 coin is heads therefore that coin is irrelevant. We know what its landed on.

The next coin is a simple heads or tails probability
>>
>>700662518
IN THE WORDS< UM WOW kys! retard, cant even read or do math
>>
>>700662509
multiply 2/3 and 1/3
here's you:
>1/3 * 2/2

Please explain how multiplying 2/3 and 1/3 is the same as multiplying 1/3 and 2/2.
>>
To you people saying 50% we do not know witch coin will be heads.
Think of it like this we haven't flip any coins yet we go to do both at the same time then we get this view of the future that one of the coins will be heads.
>>
>>700662569

So it doesn't say the first coin landed heads. Glad we cleared that up.

Answer is 1/3

3 equally likely outcomes containing at least one heads coin

HH
HT
TH

HH is 1 of those 3

1 of 3

1/3
>>
>>700662655
I can as well just multiply that for you as well, but for that you have to put the marble that was picked in the first event back into the bag.
>>
>>700662608
>1 coin is heads therefore that coin is irrelevant. We know what its landed on.

Which coin?
>>
>>700654414
>mfw people think that flipping a coin is actually 50/50, it's 51/49 in favour of the side it was already on. It's slightly more likely to land on heads for example, if it was on heads to begin with
>>
>>700662559
Yeah, my bad. I thought I could teach a /b/tard the definition of independent events, but it was hopeless.
>>
>>700662428
It says at least one coin not one coin is heads
>>
>>700662720
Jesus, you're so fucking stupid.
>>
>>700662608
EX-fucking-actly. its retards that have their own brand of maths, aka their own retarded logic. Imagine what its like in there brains. they cant even understand something involving 2 coins FUCK!
>>
>>700662358
>You take the possible combinations and then rearange them to make more...

Anon...

Because H and T are functionally identical in value and use. There's only three results in the first place from flipping two coins

HH
HT
TT

TH while it's different, is functionally identical to the test as HT, and using it would just be re-arranging the combinations to make more. So if we want to not re-arrange the combinations. We now disqualify TT

There you go, two choices.

HH or HT, which is 50%.
>>
>>700654414
33%
>>
>>700662859
>There's only three results in the first place from flipping two coins

there are 4 results:

HH
HT
TH
TT

HT and TH are 2 separate and equally probable outcomes, so you are already incorrect right from the get go.

>HH or HT
or TH

1/3

If you think HT and TH are the same, read this >>700661294
>>
>>700662803
You're the stupid one, 1/3 * 2/2 because if I take one out there are obviously not still 3 left in the fucking bag. His fault he typed it wrong to begin with.
>>
>>700654414
1 coin = 50%
1 coin = 50%
the possibilities are accumulable (even if the flips is at the same time), so the 50% of 50% is 25%.

Let's say why is not 1/3. There are 4 possibilities for the coins (F/F, F/D, D/F, D/D, and YES D/F and F/D are TWO possibilities), and only one is the one you're looking for, so.... that's 1/4 = 25%
>>
>>700662677
OMG you need to be purged, the fucking coins dont exist, THERE IS NO FIRST COIN you retard. its just A coin. It placement in the room, when it was made, what colour it is, THIS DOESNT MATTER, but i cant even explain it to someone as dumb as you. The facts that one coin is decided is a fucking fact, you reason you are thinking about which coin came first, is because you are mentally retarded and should be neutered (that's when you stop something breeding)
>>
>>700661045

Anon your premise is flawed, because it's counting the number of times two coins come up with one coin heads (75%), and the number of times two coins both come up heads (25%).


But that 75% Takes into account the fact that sometimes it can roll a TT, which means you're not properly disqualifying the TT result.


With TT disqualified, its a 100% chance that one coin will be heads, and a 66% chance that both coins will be heads.
>>
>>700662682
dude holy shit you guys think youre so smart with your grade nine probability .

One coin is gonna land heads it doesnt matter which fucking coin it is ONE coin is heads.

Ignore that fucking coin the question literally becomes heads or tails chance.

IE 50%
>>
>>700662793
Mate you are still thinking about if its the left or right one, i cant explain this to you
>>
ok let's go
http://cheesespin.net/
>>
>>700663106

At least one coin landed heads, so Tails - Tails is ruled out, leaving 3

1/3

>>700663109
>The facts that one coin is decided is a fucking fact

Which coin?

if you can't tell us which coin landed heads, then either coin could be tails, which means there are 3 equally probable outcomes containing at least one heads coin

Heads - Heads
Heads - Tails
Tails - Heads

1/3

Refer to image here >>700658530

if we knew the first coin landed heads, the answer would be 1/2

If AT LEAST 1 coin landed heads, the answer is 1/3
>>
>>700654414
> at least one of them landed heads
This mean we have the possible cases:
1st heads, 2nd tails
1st tails, 2nd heads
1sr heads, 2nd heads
The possibility that both landed heads is this 1/3
>>
>>700663321
>But that 75% Takes into account the fact that sometimes it can roll a TT

No, it doesn't. The if conditions omit all TT results.

Answer is 1/3

Flip 2 coins 1000 times. On average, you will get

Heads - Heads 250 times
Heads - Tails 250 times
Tails - Heads 250 times
Tails - Tails 250 times

750 of those contain at least one heads
250 are both heads

250/750 = 1/3

>it doesnt matter which fucking coin

Unless the coin is specified, then it could still be tails, therefore the answer is 1/3
>>
>>700663730
retard detected
>>
>>700663400
fuck your image and theoretical bullshit math.

The reality is one coin is heads That coiun is heads simple as that. Doesnt matter if its the first or second because
HT
and
TH
are the same fucking outcome. 1 coin heads 1 coin tails.

We know 1 coins heads the probability of the next coin being heads is 50/50

honestly if you dont get this theres no hope for you
>>
>>700663109
I'll try again to coins where flipped you don't see these coins, your friend who sees both tells you at least one is heads.
>>
>>700663831
It's not the same outcome. You'll learn this when you advance is math classes.
>>
ANYONE
who thinks this is 1/3 has no comprehendsion skills whatsoever.
The question is not asking about the order of the coins or all 3 possible outcomes its simply asking what is the chance of a coin landing heads.
Its worded to confuse and obviously it fucking confused you idiots
>>
>>700656677
ARE YOU FUCKING RETARDED ? WHAT WORD DON'T YOU UNDERSTAND WITH "LAST ONE" YOUR SECOND ASSUMPTION IS BULLSHIT
>>
>>700663400
Someone need to sit you down and calmly explain, there is no which coin, the coins no exist, in this maths, the odering doesnt matter, we know ones head. it DOESNT FUCKING MATTER OR MEAN ANYTHING WHEN YOU IDIOTS SAY "which coin" please, you are far to dumb to understand this, go watch some MLP or something
>>
>>700663981
THANK YOU FUCK.
>>
>>700663927
what are you even saying. 1 coin is heads atleast, if you dont agree with that, you cant FUCKING read.
>>
>>700663831

>fuck math

Yes, I'll take a large fries with that.

>HT
>and
>TH
>are the same fucking outcome

Oh wow, you actually really ARE retarded. Now I feel kinda bad.

HT and TH are not the same, you simpleton. Read this >>700661294 to see why.

1/3
>>
>>700658530
"last one landed on heads". so we know wich one landed on heads. so it's 1/2
>>
>>700663814
Stop looking in a mirror then
>>
>>700663971
>The question is not asking about the order of the coins

We know.

>or all 3 possible outcomes

We know.

>its simply asking what is the chance of a coin landing heads.

no, it isn't you simpleton.

It's asking
>What is the probability that both coins landed heads given that at least 1 coin landed heads?

the answer to that is 1/3

>>700663976

What?
>>
>>700664181
It says ATLEAST one, you dipshit.
>>
>>700664113
Let me tell you how this really works:

There are 4 possible combinations for the coins:

HH
HT
TH
TT

Both HT and TH are possible combinations you may get, HT and TH represent the 50%, so HH is 25%.

Even HT and TH are the same, both are possible outcomes, you can have either HT or TH. Argue that
>>
>>700664110
Did you even read what I said
>>
>>700664113
Ok genius.

Read the question again focus realllly hard.

What you are answering is a question of possible outcomes in terms of two coins being flipped.
The question does not care about the 3 possible outcomes therefore
HT
TH
ARE the fucking same its irrelevant to this question. The coins do not exist this is a simple problem solving trick question in grade 8 possibility trying to trick genius's like you who can learn the textbook but not the ability to THINK.

* is an unflipped coin.

* H
H *

the question is asking what is the chance * lands on heads.
With the only other outcome being T
it makes it a 50% chance REGARDLESS which fucking side the coin is on.
Please use your head
>>
>>700664377
>HT and TH represent the 50%, so HH is 25%

Correct


>Even HT and TH are the same, both are possible outcomes, you can have either HT or TH.

Correct. I wasn't arguing against that.

So the answer is 1/3
>>
>>700663804
you doun't know how to math:

1000 is the total outcome, so 750 is thetime you loose, 250 the times you win. Do the % of the times you loose in front of twe wins means NOTHING. You have to math 250/1000 because 1000 is the total amount of times you flip the coin, and with 1000 flips, 25% of the time you will get HH
>>
>>700664110
Friend tell you at least one is heads. Did ya miss that
>>
1/3
Heads Tails
Heads Heads
Tails Heads
>>
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can someone here balanced a coin on the head of their dick??
>>
>>700664605
again, flipping 1000 times, 250 of that 1000 flips will be HH, so why 1/3?
>>
>>700664618
unless of course we knew one coin HAD to land heads in which case this would be a really fucking simple question of the chance of ONE coin landing heads.

I cant believe how stupid this thread is. Is the one other guy in here who can actually grasp this simple concept
>>
>>700664470
This

Yall motherfuckers need to learn logical thinking
>>
depends if you are in Euclidean space
>>
4 possibly answers given the problem and the awareness of the target.
25% per initial question.
33% bayes rule.
50% if sections are segmented.
0% coin not flipped.

This of course doesn't take into consideration the coin lands on its side.
>>
>>700664764
Let's take if different now. We donpt have 2 coins, we have 1000 coins. The oucomes are still 3, so following your logic, the possibilities for all those coins fo be heads are 1/3
>>
If you say anything other than 1/3 you are a fucking retard.

You have 3 total possible outcomes given that one of the 2 flips definitely landed on heads
Heads / Heads
Heads / Tails
Tails / Heads
>>
>>700661250
You probably meant that the other way around.
>>
>>700664750
Because you don't count the T/T happening because atleast one of the coins has to be heads to be counted.
>>
>>700664470
>probability that both landed heads given that at least one of them landed heads

Ok so we flip a coin. If the first is tails, the other coin must be heads. If the first is heads, the other coin may be heads or may be tails. I see three possible outcomes. Only one of them is heads/heads.
>>
>>700654414
1/3 ez
>>
>>700665004
my god this is NOT a question of 1000 coins and the probability of all possible outcomes.

Man you guys are playing yourselves. The statistical chance of a coin landing on heads is 50% if the other coin is guaranteed heads the chance of HH is 50%
ITS SO PAINFULLY SIMPLE
the question is written to confuse people and send them on your train of thought.
ITS NOT 33% we KNOW what one coin is WE KNOW
>>
>>700664338
so you genuinely that if you have 2 coins, one is already heads so you flip the second coin with 2 faces, that it has what 33% chance at heads and 77% at tail. now the coin has 2 faces, how is that possible. You can assume 1 coin is 1/1, because the other outcome of tails has been removed in the question. so one coin is 1/1 (since is only has 1 outcome) the other is - 1/2, which equals 1/2, the answer is 50%. sorry.
>>
>>700664470
>What you are answering is a question of possible outcomes in terms of two coins being flipped.

Nope. I am answering the question,
'What is the probability that both coins landed heads given that at least 1 coin landed heads?'

Here's how you get the answer

for a 2 coin flip:
Probability both land heads = 1/4
Probability at least 1 lands heads = 3/4

Probability both heads given at least 1 heads = (1/4) / (3/4) = 1/3

this is basic conditional math and you do not need to be a genius to understand it.

>HT
>TH
>ARE the fucking same

I've explained already how they are not the same. Just because they LOOK the same to retards, does not mean that they are not 2 distinct and separate outcomes with equal probability of occurring.

>this is a simple problem solving trick question

No, it's a basic conditional probability math question.

>* H
>H *
>the question is asking what is the chance * lands on heads.

No, it's asking,
'What is the probability that both coins landed heads given that at least 1 coin landed heads?'

And the answer to that is 1/3
>>
>>700661675
Why? Ur the retard
>>
>>700665218
But we don't know which coin is heads. That's the important part.
>>
>>700665218
Being this mad because you're dumb.
>>
Those aren't regular coins no one uses dollar coins.
>>
>>700664750

Because you're calculating the probability based on the condition that there is at least one heads coin

At least 1 heads coin = 750 times
Both Heads = 250 times

250/750 = 1/3
>>
>>700659475
it doesn't matter which one landed heads as long as at least one of them did..
>>
50 %
>>
>>700665150
ok you see 3 different outcomes but we arent looking at what is the chance in all the outcomes we are looking at it statistically

I understand your train of thought so please try and understand mine. If you have two coins please put one of the table in heads.

Now flip a coin on the left or right side.

What is the chance of that coin landing on heads?

The question you are answering is not this one.

The statistical chance of it being heads heads is 50% regardless which side or possible orders the coins can land in. WE KNOW a coin lands heads
>>
>>700659546
(Probability of event (A n B)) DIVIDED BY (Probability of event B)
sucker.
>>
>>700655075
yeah who needs jobs when you can du-nuffin?
>>
>>700665245
The oucome will be exactly the same if we flip one coin before another. As you say, this is so simple, basic maths.

You flip one coin, you have 50%, then you flip another coin, again, you have 50%. The % are accumulable, this is teached in school, is Always accumulable. So 50% of 50% are 25%.

Let's flip now 3 coins, we have now 9 different outcomes, but each coin has 50% of being H or T, no matter the final outcome. So you have fo flip each coin, and with everyone you have 50%, at the end, the possibilities to habe HHH is 12,5%.
>>
If one is guaranteed to be heads then its up to the other, so 50/50
>>
>>700665218
>if the other coin is guaranteed heads

It isn't. Are you understanding yet?

>>700665239
>if you have 2 coins, one is already heads so you flip the second coin with 2 faces, that it has what 33% chance at heads and 77% at tail.

lol 33 + 77 = 110 you retard, and no, the probability in that situation would be 1/2 or 50%.

The probability in OP question is 1/3
>>
>>700654414
1/3
>>
>>700665851
you're missin one thcombo variable 'cause is a possible outcome
>>
50%

HT and TH are the same in this case
>>
>>700665600
That's because the question asked is not that one!

The question assumes at least one landed heads, which implies both were thrown. While we know one lands heads, we don't know which one!

By posing the question your way, you are assuming the first coin is heads. This is wrong, it could very well be tails!
The first one landing heads or tails is two separate outcomes.
>>
>>700665803

On most coins the head side weights slightly more. A US quarter for instance has a 51% chance of landing tails side up.
>>
>>700665600
>If you have two coins please put one of the table in heads.

That's not what happens in the OP question, you simpleton.

you are FIXING a coin to be heads.

OP question does not fix a coin. Either coin could be tails.

In your scenario, one specific coin can NEVER be tails

Do you understand the difference?

The answer to your scenario is 1/2

The answer to OP question is 1/3.
>>
Ok 50%ers why is

HH
TH
HT

Not 1/3
And please don't tell me

HT & TH are the same

If they were truth tables would be completely useless
>>
>>700665763

Yeah. That's 1/3.

>>700665776
>Let's flip now 3 coins, we have now 9 different outcomes

there are 8 outcomes for a 3 coin flip. I'm not going to engage with you anymore. You are mathematically illiterate and English isn't your first language.

Answer is 1/3. Deal with it.

Source
http://courses.cs.washington.edu/courses/cse312/11wi/slides/04cprob.pdf
>>
>>700665953
Where is this combo missing?
I don't see the error anywhere.

thCombo is Tails/Heads
htCombo is Heads/Tails
hhCombo is Heads/Heads

ttCombo is not a thing because we are guaranteed one head, so I reroll those outcomes.
>>
>>700666050
>>700666009
>>700665851
>>700666179
>>700665776
>>700665600

The question itself is a bitch.
Both trains of thought are logical depending on how you interpret the question.
A simple line added at the top
"Two coins are thrown simultaneously" and the 1/3 would be correct however the lack of this line leaves the question completely open to interpretation in which case assuming we know one coin has landed heads 1/2 is correct.

Really you guys are arguing over how you read the question both your answers are right
>>
>>700665851

Confirming 1/3

50% retards BTFO

>>700665967
>HT and TH are the same in this case

No. Read >>700661294

>>700666429
>The question itself is a bitch.

no, it's pretty basic conditional probability math.

>Both trains of thought are logical depending on how you interpret the question.

There is one correct answer. Don't make excuses.

>A simple line added at the top
>"Two coins are thrown simultaneously" and the 1/3 would be correct

1/3 is correct whether the 2 coins were flipped simultaneously, sequentially or a single coin was flipped twice. in all cases where at least 1 coin/flip landed heads, you get 2 heads 1/3 of the time.

Answer is 1/3 whichever way you interpret the flip.
>>
>>700666429
im the 50% guy and this is the only thing ill agree with in this thread.

I said it before I understand the train of thought behind 1/3 its simple probability but with the wording of this question i would say 1/2
>>
>>700666429
It says were flipped we don't know if they were flipped one at a time or simultaneously and it doesn't matter. It say at least one is heads therefore 1/3.if it said one is heads then it would be 1/2.
>>
>>700666896
>im the 50% guy and this is the only thing ill agree with in this thread.

That's because you now realize you were wrong and are doing damage control

>no g-guys Im not r-r-retarded. it's the w-w-way the question is worded

kek
>>
>>700666861
>>700666861
>1/3 is correct whether the 2 coins were flipped simultaneously, sequentially or a single coin was flipped twice. in all cases where at least 1 coin/flip landed heads, you get 2 heads 1/3 of the time.
>Answer is 1/3 whichever way you interpret the flip.

no because adding that line would negate the train of thought that one coin has already landed as heads.

Which is very easy to think considering is is acknowledged in question that one coin is heads.
It is completely up to interpretation stop being buthurt
>>
>>700666429
Well, the people who think it is 50/50, it's actually 1/4
>>
>>700666896
For it to be 50% it would have to say 1 is heads. What do you think the wording would have to be for the answer to be 1/3?
>>
>>700667053
It is 50% tho
one coin is H
leaving another coin to be H or T
you are still overcomplicating it
>>
>>700667089

You're an idiot.

You are told in the question that

>2 coins were flipped
>WERE flipped

Already happened.

Then you are told

>At least one landed heads

So that's all the information you have, and based on that information, the probability that both landed heads is 1/3.

It doesn't matter if one coin was flipped at 1 o clock, and the other coin was flipped at 3 o clock.

It doesn't matter if they were flipped at the same time.

the answer is 1/3 in all cases.

Deal with it.
>>
>>700667177
At least one coin is H, why do you not think that matters?
>>
>>700654414
>oh look, another conditional probability thread
>ITT: anons assuming a clockwork universe just because we tell them a coin landed heads

opinion discarded if you answer anything but 1/3
>>
>>700666896
If the answer is 1/3.then what would be the questions wording?
>>
>>700667158
>leave it to a python programmer to fuck up something this simple
>>
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>>700667158

Your code is incorrect here

elif (firstCoin == "Tails"):
second coin = "Heads"

you are fixing a coin this way.

that is why you get
Tails/Heads = ~50%
and
Heads/Tails = ~25%

Both of those should occur the same amount of times on average.

you need to do 2 random coin flips.

then ignore cases where no coin was heads

count all cases of at least 1 heads coin

count all cases of both heads

divide #bothHeads by #at least 1 heads

Code related

1/3
>>
Answer is defs 1/3

1/2 only works if the question stated the first coin landed heads but since we dont know we have to look at the possible outcomes
>>
god im gonna get absolutely bombed for this

yeh I see its 1/3 now I understand you were right...youre all still fuckwits
>>
>>700667868
We can leave now guys
>>
>>700667868
This is bait no one admits theyre wrong on /b/
>>
>>700667158
I am aware, see my previous post. This was for the people who think it is 50%. Their version locks a coin to heads, which is what this example does. My first example, the correct solution, displays it being 1/3

>>700665851
>>
>>700667868
Just goes to show you can educated the retarded
>>
>>700667868

>hey guys, I was wrong but you're the retarded ones

kek

At least you are man enough to admit when you are wrong.

you are now part of the 1/3 family.

Welcome aboard.
>>
1/3 cuz
HT NOT GOOD
TH NOT GOOD
HH GOOD
You fags
>>
>>700668243
meant for
>>700667708
>>
>>700654414
Possibilities

P1 - Good
Coin 1 (Heads)
Coin 2 (Heads)

P2 - Bad
Coin 1:(Tails)
Coin 2:(Heads)

P3 - Bad
Coin 1:(Heads)
Coin 2:(Tails)

I'd give it a 1/3 chance to be honest.
>>
>>700667868
All those post are you? What made it finally click?
>>
>>700668442

Ah ok then.
>>
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>>700654414
>>
>>700654414
Sample Set:
HH
HT
TH
TT

One of them landed heads, so TT is not a possibility.
That means the set is {HH, HT, TH}. Asking for the probability for both to be heads means that the answer has to be 1/3.
>>
>>700668473

he was only pretending to be retarded
>>
>>700668550
I've never seen a slovenian euro, who's on it?
>>
if its given that one of them will always land heads , then the probability of them both landing heads is just the same as one coin landing heads, 1/2.

We can prove this because , if the always heads coin has a probability of 1/1 of landing heads, (or just '1') and the other coin has a 1/2 chance of landing heads.

To find the probablility of one thing AND another thing happening you multiply the probabilities.

1x0.5=0.5
>>
>>700668835
You need to read the entire thread, it has been explained over and over why this is wrong.
>>
is this just the monty hall problem?
>>
>>700668835
>if its given that one of them will always land heads

It isn't.
>>
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You're all retarded.

The question cannot be answered because it is both self-referential and changes between probabilistic and deterministic outcomes.

You can't just "guarantee" that at least one of the coins is heads. If you do, then coins are not "regular" or they are not actually being "flipped" (i.e., determined outcome).

Employ some critical though for once in your life.
>>
>>700669004

No but it's similarly counter intuitive.

Conditional probability often is difficult for people.
>>
Im not sure why some people overcomplicate this explanation.

There are 3 different permutations of how the coins can result given the restrictions stated in OP's picture.

1. HH
2. HT
3. TH

Each of these permutations have an equal chance of becoming the result, and since only one permutation out of three has 2 Heads as the result, the answer is 1/3.
>>
>>700669094
>You can't just "guarantee" that at least one of the coins is heads.

I just flipped 2 regular coins. At least 1 of them landed heads. Now you tell me the probability that both landed heads.
>>
>>700669314
>At least 1 of them landed heads.
How do you know this?

How can you apply future events to questions based on past events?

The question is self-referential.
It cannot be answered.
>>
>>700669546
The king has two children, one of them is his son. What are the chances of his son to have a brother?
>>
>>700669507
Uhh because its stated in the picture?

Wot
>>
>>700669684
Yeah, and I can state that you went back in time and killed your own grandfather before your father was born.

The answer is still complete nonsense.
>>
>>700669674
That doesn't answer the question.
>>
>>700669507
>>700669546
this is the laziest trolling. conditional probability, you start with the sample space, two coins being flipped, then you eliminate possibilities that cannot exist according to the restrictions in the problem.
>HT
>TH
>TT
>HH

hmm looks like we need to eliminate TT, that result doesn't happen according to the problem.
>HT
>TH
>HH
out of our remaining samples, 1/3 of them are the result HH, so the answer is 1/3.
>>
The Chance of Land in head of one coin is 1/3
That multiplied for the other coin is the chance that both have of landing on head

1/3 * 1/3 = 0.11111111111 ~ 11%

This is a way to calculate, pretty primitive, not precise at all
>>
>>700669546
>How do you know this?

I looked at them, you retard.

>How can you apply future events to questions based on past events?

Knowing the outcome is a future event for you.

If you want to get all philosophical, you've come to the wrong neighborhood, motherfucker.

>The question is self-referential.
>It cannot be answered.

It's a basic conditional probability question, and can very much be answered.
>>
>>700669850
>hmm looks like we need to eliminate TT
That's not how that works.

Again, you're changing the nature of the question itself based on the outcome.

It's self-referential.
>>
>>700669929
>Knowing the outcome is a future event for you.
No, it's a past event as you've told it to me and made it into a part of the question itself.

The question is self-referential.
>>
>>700669768
>The answer is still complete nonsense

>math is nonsense

Kill yourself, lad.

>>700669978
you're changing the nature of the question itself based on the outcome.

no, faggot, he's getting the probability based on the condition specified in the question.
>>
>>700667655
I just used python since it's easy to quickly put something together, honestly the first time I used it in a long time. I program in a wide variety of languages. Sure, all the main stream ones, but a wide variety nonetheless.

Also, see this
>>700668243
>>700665851

All I was explaining was that the people who think it's 1/2 or 50% are wrong even in their own scenario, it's actually 1/4 or 25%. I don't agree with them, I agree with my original solution, 1/3.
>>
>>700670064

Retarded or trolling?
>>
>>700669978
>From the wikipedia page for conditional probability
conditional probability is a measure of the probability of an event given that (by assumption, presumption, assertion or evidence) another event has occurred.

so you're saying that the entire subject of conditional probability is self-referential and therefore doesn't exist? The concept of "this happened, so whats the probability of that happening" would be considered self-referential to you.

>again, this is the laziest form of trolling.
>>
>>700670064

this is b8
>>
>>700670162
>no, faggot, he's getting the probability based on the condition specified in the question.
No, claiming that at least one of the answers must be heads is deterministic.

It's a premise based on an outcome.
It's self-referential.
>>
>>700670279
You'll realize I'm right.
>>
100%
fucking retards
>>
>>700670259
>(by assumption, presumption, assertion or evidence) another event has occurred.
You're discussing independent events.

This is an event dependent on itself, and thus self-referential.
>>
>>700668835
Stop! Reread the question
>>
>>700670221
Smarter than you, fuckface.
>>
>>700670363
please explain further.
>>
>>700670320
/thread
>>
>>700670292
>No, claiming that at least one of the answers must be heads is deterministic.

That's called a condition, you simpleton. Hence the term
>Conditional probability

As in

What is the probability of event A given event B?

Now fuck off you trolling spastic before I self-referential your nutsack down your throat.
>>
>>700670313
I realize you're a faggot.
>>
>>700670460
>What is the probability of event A given event B?
No, the question in the OP is the equvilent of "What is the probability of A given both A and B have happened?"

It's self-referential.
>>
>>700669546
Someone see the coins and to fuck with you tells you at least one of the Is heads
>>
The probability of that both land in head is 0.11111... (1/3*1/3)
But we know that at least one landed on head, which may confuse you, because is only one coin and the possibility of landing in head is 1/3 but that changes nothing, because two coins were thrown, so the possibility is still 0.1111 respectively
>>
>>700670579
please explain further, what are A and B?
>>
>>700655061
More like
Heads heads
Tails head
Head tails
>>
its gonna be 50%, if there is one that's always gonna be heads, then the chances of both being heads should matter only on the undecided flip,which will be 50/50, he only ever asked about the chances of both being heads
>>
>>700669674
The way its word it would be 50%
>>
>>700670669
H H
H T
T H
T T
>>
>>700668835
dont go there bro believe me its not worth it.

Its 1/3
>>
>>700670610
So he's giving the answer in advance?

How is this a normal coinflip then if at least one of the coins is predetermined?
>>
>>700654414
probability of how coin lands is not dependent on the other coin, so even if the first coin landed heads, the probability of the other coin landing heads is 50/50.
>>
>>700669546
Learn to read
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