Epicmafia

Probability Problem

over 7 years

Say that a couple has a (11/23)^k probability of having exactly k children, k > 0.

a) Find the probability that a couple does 0 children.

b) Find the probability of a couple having exactly 2 daughters. (a children will become a girl with a probability of 50%)

Elfen

over 7 years

mandevian says

OH yeah I think I got it. Summation will start with k=2. Therefore 121/552

It's not made out of the same summation, actually finding the formula is much easier than calculating the final result, which needs series theory to be calculated.

Finding the final summation formula is enough.

mandevian

over 7 years

OH yeah I think I got it. Summation will start with k=2. Therefore 121/552

Elfen

over 7 years

mandevian says

Have not thought it through but I think it is half of 11 by 12

it's much lower

illuminati

over 7 years

Probability Problem:

Chances of OP ever having intercourse and consequently children

mandevian

over 7 years

Have not thought it through but I think it is half of 11 by 12

mandevian

over 7 years

I will try to solve the othet one. Still have not figured out the approach.

Elfen

over 7 years

When I posted it I had found only A, I found B afterwards, so I'm leaving it here for whoever wants to solve it, so it was indeed a help post, and thank you

mandevian

over 7 years

Fam I thought you needed help. If you already know the answer to other one as well then I won't spend time on it.

Elfen

over 7 years

that's correct about zero children @mandevian

mandevian

over 7 years

For zero children

P (0)= 1-p (1)+p (2)......+p (infinity)

So let 11/23 =a

P (0)= 1- summation for n = 1 to infinity a^n

= 1- (-a/(a-1))

= 1-(-11/23/(-12/23))

=1-(11/12)

=1/12