If the odds of a 25yo conceiving per month are 0.25 then the

>>>/wsr/

Not your homework board.

>>8557316
No.

If you flip a fair coin, then flipping twice doesn't guarantee a heads and a tails.

>>8557392

That's why I said average.

>>8557316
>>8557396
Lrn2binomial-probabilly

Ostriches can't do probability.

>>8557316
This is a geometric distribution, with expectancy 1/p=4, so yes. Large standard deviation thoough, so it's worth fuck all.

>>8557425
source?

>>8557316
1 = 0.25 + 0.25*0.75 + 0.25*0.75^2 + 0.25*0.75^3 ........
The expected number of months until conception is a weighted average of each possibility, so
EV = 1*0.25 + 2*0.25*0.75 + 3*0.25*0.75^2 + 4*0.25*0.75^3 ......
EV = (1*0.25 + 1*0.25*0.75 + 1*0.25*0.75^2 ....) + (1*0.25*0.75 + 1*0.25*0.75^2 + 1*0.25*0.75^3 ...) + (1*0.25*0.75^2 + 1*0.25*0.75^3 + 1*0.25*0.75^4 ...) ... = 0.25*(1/(1-0.75)) + 0.25*(0.75/(1-0.75)) + 0.25*(0.75^2/(1-0.75)) + 0.25*(0.75^3/(1-0.75)) ...
Obviously, EV = limit n -> infinity of sum from k=0 to n of 0.25*(0.75^k - 0.75^(n+1))/(1-0.75) = limit n->infinity of 0.25*(1 - 0.75^(n+1))/[(1-0.75)^2] - (0.25*(n+1)*0.75^(n+1))/(1-0.75) = 0.25*(1-0)/[(1-0.75)^2] - 0 = 1/(1-0.75). the expected number of months is 1/0.25 = 4 months.

Stop trying to assure yourself she's not pregnant. She is, your life is over. Best you can do now is hope it's Chad's and not yours.

>>8557316
>If the odds of a 25yo conceiving per month are 0.25

They're closer to 0.13~0.15

>>8557316
>>ITT: people who don't know the definition of odds

odds(A)=P(A)/P(not A)

so the probability of her conceiving in a given month is 20%

thus average time is 1/.2=5 months

>>8557316
There's a name to this type of situation (where there's probability p that something happens per unit time, and you want to know how long before it happens)
https://en.wikipedia.org/wiki/Geometric_distribution