Question

The number of girls in three-child families in a certain geographic area is investigated. Of 212 families with exactly three children, there were 24 with no girls, 81 with one girl, 76 with two girls, and 31 with three girls. If it is desired to fit these counts to a binomial distribution, then what is the estimated value of the parameter p, the probability that an individual child is a girl, rounded to three decimal places?

Answer 1

p = 0.513

Explanation:

There are 212 families with exactly 3 children. So in all, there are 212*3 = 636 children.

Of those,

The number of girls is:

81 + 76*2 + 31*3 = 326

That is, 326 girls out of 636 children.

Then

`p = (326)/(636) = 0.513`