Question

Destion 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 lethood that each baby wil beag, but assume that the method has no efect, so the probability of a girl is 0.5. Assume that the groups consist of 25 couples. Complete parts (athrough (c) below. a. Find the mean and the standard deviation for the numbers of girls in groups of 25 births The value of the mean is-O (Type an integer or a decimal. Do not round.)

Answer 1

$\\ Let\ X\ denotes\ the\ number\ of\ girl\ babies\ out\ of\ 25.\\ Given\ that\ probability\ of\ a\ girl\ is\ 0.5.\\ Then,\\ X \sim N(n = 25,\ p = 0.5)\\ (a)\\ Mean = np = 25*0.5 = 12.5\\ SD[X] = \sqrt{np(1-p)} = \sqrt{25*0.5*(1-0.5)} = \sqrt{6.25} = 2.5$