5. A young child wonders what causes women to have babies. For each woman who lives on hier block, she observes whether her hair is gray and whether she has young children, with the results shown in Table 8.23.

a) Construct the 2 x 2 contingency table that cross-classifies "gray hair" (yes, no) with "young children" (yes. no) for thesc nine women

b) Treating "young children" as the response vanable, obtain the conditional distributions for those women who have gray hair and for those who do not. Does there seem to be an association?

c) Noticing this association, the child concludes that not having gray hair is what causes women to have children. Use this example to explain why association does not necessar- ily imply causation (Chapter 10 discusses the connection between association and cau- sation.)

TABLE 8.23 Woman Gay Hair Young Children Andrea No Yes Mary Yes No Landa No Yes Jane No Yes Maureen Yes No Judy Yes No Margo No Yes Carol Yes No Donga No Yes