Refer to Problem 11.1. Suppose that we expressed the data with a 3 × 2 partial table of drug-by-response for each subject, to use a generalized CMH procedure to test marginal homogeneity. Explain why the 911 + 279 subjects who make the same response for every drug have no effect on the test.

Data from Problem 11.1:

Refer to Table 8.3. Viewing the table as matched triplets, construct the marginal distribution for each substance. Find the sample proportions of students who used marijuana, alcohol, and cigarettes. Test the hypothesis of marginal homogeneity. Interpret results.

Table 8.3:

Alcohol, Cigarette, and Marijuana Use for High School Seniors Marijuana Use Alcohol Cigarette Use Use Yes No Yes Yes 911 538 No 44 456 No Yes 3 43 No 2 279