Center for Epidemiologic Studies. On a scale of 0 to 60, a score of 16 or
higher was classified as depression. Table E7.14 gives the average CES-D
score for the two genders. Use attest to compare the males versus the
females and draw appropriate conclusions.7.15 A study was undertaken to study the relationship between exposure to
polychlorinated biphenyls (PCBs) and reproduction among women oc-
cupationally exposed to PCBs during the manufacture of capacitors in
upstate New York. To ascertain information on reproductive outcomes,
interviews were conducted in 1982 with women who had held jobs with
direct exposure and women who had never held a direct-exposure job.
Data are summarized in Table E7.15. Test to evaluate the e¤ect of direct
exposure (compared to indirect exposure) using each measured charac-
teristic. In each case, name the test and state clearly your null and alter-
native hypotheses and choice of test size.
TABLE E7.15
Exposure
Direct (n¼172) Indirect (n¼184)
Variable Mean SD Mean SD
Weight gain during
pregnancy (lb)25.5 14.0 29.0 14.7Birth weight (g) 3313 456 3417 486
Gestational age (days) 279.0 17.0 279.3 13.57.16 The following data are taken from a study that compares adolescents
who have bulimia to healthy adolescents with similar body compositions
and levels of physical activity. Table E7.16 provides measures of daily
caloric intake (kcal/kg) for random samples of 23 bulimic adolescents
and 15 healthy ones. Use the Wilcoxon test to compare the two pop-
ulations.
TABLE E7.16
Bulimic Adolescents Healthy Adolescents
15.9 17.0 18.9 30.6 40.8
16.0 17.6 19.6 25.7 37.4
16.5 28.7 21.5 25.3 37.1
18.9 28.0 24.1 24.5 30.6
18.4 25.6 23.6 20.7 33.2
18.1 25.2 22.9 22.4 33.7
30.9 25.1 21.6 23.1 36.6
29.2 24.5 23.8EXERCISES 277