Question: A large study of child care used samples from the data tapes of the Current Population Survey over a period of several years. The result is close to an SRS of child-care workers. The current Population Survey has three classes of child-care workers: private household, non-household, and preschool teacher. Here are data on the number of blacks among women workers in these three classes:

Total Black

Household 2455 172

Non-household 1191 167

Teachers 659 86

a) What percent of each class of child-care workers is black?

b) Make a two-way table of class of worker by race (black or other)

c) Can we safely use the chi-square test? What null and alternative hypotheses does X² test?

d) The chi-square test for this table is X² = 53.194. What are its degrees of freedom? Use table E to approximate the P value.

e) What do you conclude from these data?