What are the mean and standard deviation for the two probability distributions for the number of boys and the number of girls in families of four from Exercise 11.6.10?

Data from Exercise 11.6.10

About 51% of babies born in the United States are boys. Let’s assume that the probability of a birth resulting in a boy is 0.51 for all U.S. births. Suppose a couple decides they want to have four children.