# Out of 320 Families with 5 children each, what percentage would be expected to have a) 2 boys and 2 girls and b) at least one boy? Assume equal probability for boys and girls

1
by praveentiwari4
i ll send you
the distribution of typing mistakes committed by a typist is given below ::
no of mistake per page 0 1 2 3 4 5 and no of pages 142 156 69 27 5 1 assuming a posson mode, find out the expected frequencies:
nope i didn't learn poisson's mode
oh so is there any other way through which i can find out my answer

2014-04-24T14:32:50+05:30
There are 320 families with 5 children
so a family can have
(boys,girls)=(0,5)(1,4)(2,3)(3,2)(4,1)(0,5)
a)
for 2 boys and 2 girls
probability=2/6=1/3
no. of families=320(1/3)=107 (.app)
33.33% of families
b)
for at least boy
proablilty=4/6=2/3
no. of families=214 (,app)
66.66% of families

for at least boy
proablilty=5/6
no. of families= 267 (,app)
83.33% of families
but manit total is not matching
its exceeding 100
83.33%+33.33%=116.66% some mistake
nope u got it wrong see atleast 1 boy case includes familie with 2 boys and 2 girls so u can add them both ok