Suppose that a family has four children, and each child is equally likely to be a boy or a girl. 

a. Write out the sample space of 16 possible outcomes. (For example, use the notation B1G2G3B4 to mean that the first child is a boy, the next two are girls, and the last is a boy.) 

b. Which outcomes comprise the event that boys (strictly) outnumber girls in the family? 

c. Determine the probability that all four children are of the same sex. 

d. Which is more likely: the family has 2 children of each sex or 3 of one sex and 1 of the other sex? Justify your answer with appropriate probability calculations.