Find the expected number of boys in a family with 8 children, assuming the sex distribution to be equally probable.

Let n and p be the parameters of the binomial distribution.

Let, p = probability of having a boy in the family

Given, p = q

Since, p + q = 1

⇒ p + p = 1

⇒ 2p = 1

Given, n = 8

The expected number of boys = np

= 4

The expected number of boys = 4

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