Introductory Biostatistics

6.5 A matched case–control study on endometrial cancer, where the expo-

sure was ‘‘ever having taken any estrogen,’’ yields the data shown in

Table E6.5. Test to compare the cases versus the controls; state clearly

your null and alternative hypotheses and choice of test size (alpha level).

TABLE E6.5

Matching Controls

Cases Exposed Nonexposed

Exposed 27 29

Nonexposed 3 4

6.6 Ninety-eight heterosexual couples, at least one of whom was HIV-

infected, were enrolled in an HIV transmission study and interviewed

about sexual behavior. Table E6.6 provides a summary of condom use

reported by heterosexual partners. Test to compare the men versus the

women; state clearly your null and alternative hypotheses and choice of

test size (alpha level).

TABLE E6.6

Man

Woman Ever Never

Ever 45 6

Never 7 40

6.7 A matched case–control study was conducted by Schwarts et al. (1989)

to evaluate the cumulative e¤ects of acrylate and methacrylate vapors

on olfactory function (Table E6.7). Cases were defined as scoring at or

below the 10th percentile on the UPSIT (University of Pennsylvania

Smell Identification Test). Test to compare the cases versus the controls;

state clearly your null and alternative hypotheses and your choice of test

size.

TABLE E6.7

Cases

Controls Exposed Unexposed

Exposed 25 22

Unexposed 9 21

6.8 Self-reported injuries among left- and right-handed people were com-

pared in a survey of 1896 college students in British Columbia, Canada.

236 COMPARISON OF POPULATION PROPORTIONS