Introductory Biostatistics

the mean atmospheric smoke (x 1 , in mg/m^3 ), and between the number

of deaths (y) and the mean atmospheric sulfur dioxide content (x 2 ),

respectively.

4.34 The following are the heights (measured to the nearest 2 cm) and the
weights (measured to the nearest kilogram) of 10 men:

Height 162 168 174 176 180 180 182 184 186 186

Weight 65 65 84 63 75 76 82 65 80 81

and 10 women:

Height 152 156 158 160 162 162 164 164 166 166

Weight 52 50 47 48 52 55 55 56 60 60

Calculate, separately for men and women, the 95% confidence interval

for Pearson’s correlation coe‰cient between height and weight. Is there

any indication that the two population correlation coe‰cients are di¤erent.

4.35 Data are shown in Table E4.35 for two groups of patients who died of
acute myelogenous leukemia. Patients were classified into the two groups
according to the presence or absence of a morphologic characteristic of
white cells. Patients termed AG positive were identified by the presence

TABLE E4.35

AG Positive,N¼ 17 AG Negative,N¼ 16

WBC

Survival Time

(weeks) WBC

Survival Time

(weeks)

2,300 65 4,400 56

750 156 3,000 65

4,300 100 4,000 17

2,600 134 1,500 7

6,000 16 9,000 16

10,500 108 5,300 22

10,000 121 10,000 3

17,000 4 19,000 4

5,400 39 27,000 2

7,000 143 28,000 3

9,400 56 31,000 8

32,000 26 26,000 4

35,000 22 21,000 3

100,000 1 79,000 30

100,000 1 100,000 4

52,000 5 100,000 43

100,000 65

186 ESTIMATION OF PARAMETERS