Question

Assume that different groups of couples use a particular method of gender selection and each couple gives birth to one baby. This method is designed to increase the likelihood that

each baby will be a girl, but assume that the method has no effect, so the probability of a girl is 0.5. Assume that the groups consist of 18 couples.
Find the expected number of girls in groups of 18 births

Answer 1

since the method is deemed to have no effect

which means probability of having a girl child is same as having a boy child which is 0.5

Total births = 18

Therefore, expected number of girls in groups should be equal to = 0.5 × 18 = 9

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