help i am retard (2 Viewers)

[kfnmpah]

someone help me i am having biggest goober moment
5 apartments
1: MM 2: WM 3: WW 4: WWWM 5: MMW (m=man w=woman)
knock on rando door and woman answers. what is the probability you are at apartment 2

 

[SnivysTrainer]

I'd say that I'm wrong, but I think the anwer might be 13C7 = 1'716. Don't quote me on that though.

I would love for someone to say whether I am right or wrong.

 

[kfnmpah]

why 13C7?

that probs has something to do with it doe for sure because there are 13 people and 7 women to choose
but i need to know the probability of choosing the apartment that has 1 woman and 1 man given that the woman answered the door

 

[braintic]

Given that you know a women answered the door, the number of men is irrelevant.

There are 7 women who could have answered the door, and only one lives in apartment 2.

So the answer is 1/7.

 

[RealiseNothing]

Given that you know a women answered the door, the number of men is irrelevant.

There are 7 women who could have answered the door, and only one lives in apartment 2.

So the answer is 1/7.

I'm fairly sure the number of men is actually relevant.

 

[michaeljennings]

Probability (Apartment 2, W)/Probability (W)

numerator = 1/10
denominator = 0 + 1/10 +1/5 + 3/20 +1/15

Answer 6/31?

 

[Crobat]

Given that you know a women answered the door, the number of men is irrelevant.

There are 7 women who could have answered the door, and only one lives in apartment 2.

So the answer is 1/7.

I'm mathmatically retarded and even I can tell the number of men are relevant to the question.

Notsureifsrs

 

[braintic]

Probability (Apartment 2, W)/Probability (W)

numerator = 1/10
denominator = 0 + 1/10 +1/5 + 3/20 +1/15

Answer 6/31?

Yes I was wrong. This is the correct answer. Though it is not the way I would have thought about the question.

 

[Drongoski]

I got 6/31 too.

 

[D94]

Standard Bayes Rule question.

P(2|W) = P(W|2)*P(2)/P(W).

Or you could draw a tree diagram to see the relationship.

6/31 is the correct answer.

 

[soloooooo]

.

 

[braintic]

Standard Bayes Rule question.

Which of course means it is not in the course.

 

[kfnmpah]

yep i realised this when i was working through it.
I was looking into this and making it way too complicated lol.

6/31 is correctamundo ! thanks y'all

 

[D94]

Which of course means it is not in the course.

As I said, draw a tree diagram since that would be very useful. It is the probability of a woman given you choose house 2, over the total probability of choosing a woman, which is essentially an application of Bayes Rule. Using terminology not in specifically mentioned 2U doesn't mean that method isn't being used to solve problems.

 

[braintic]

As I said, draw a tree diagram since that would be very useful. It is the probability of a woman given you choose house 2, over the total probability of choosing a woman, which is essentially an application of Bayes Rule. Using terminology not in specifically mentioned 2U doesn't mean that method isn't being used to solve problems.

The only question of this type in an HSC was in 1997 2 unit. They marked the wrong answer correct, and it took them 10 years to change the official answer. The controversy surrounding this question caused them to say (unofficially) that this is not in the course and would not be asked again.