Introductory Biostatistics

(d)Men with di¤erent education levels.

(e)Women with di¤erent education levels.

(f) Men versus women at each educational level.

In each case, name the test and state clearly your null and alternative

hypotheses and choice of test size.

7.8 A case–control study was undertaken to study the relationship between

hypertension and obesity. Persons aged 30 to 49 years who were clearly

nonhypertensive at their first multiphasic health checkup and became

hypertensive by age 55 were sought and identified as cases. Controls

were selected from among participants in a health plan, those who had

the first checkup and no sign of hypertension in subsequent checkups.

One control was matched to each case based on gender, race, year of

birth, and year of entrance into the health plan. Data for 609 matched

pairs are summarized in Table E7.8. Compare the cases versus the con-

trols using each measured characteristic. In each case, name the test and

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

TABLE E7.8

Paired Di¤erence

Variable Mean Standard Deviation

Systolic blood pressure (mmHg) 6.8 13.86

Diastolic blood pressure (mmHg) 5.4 12.17

Body mass index (kg/m^2 ) 1.3 4.78

7.9 The Australian study of Example 7.6 also provided these data on mon-

ocular acuity (expressed in log scale) for two female groups of subjects:

(1)Australian females of European origin

n 1 ¼ 63

x 1 ¼
 0 : 13

s 1 ¼ 0 : 17

(2)Australian females of Aboriginal origin

n 2 ¼ 54

x 2 ¼
 0 : 24

s 2 ¼ 0 : 18

Do these indicate a racial variation among women? Name your test and

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

274 COMPARISON OF POPULATION MEANS