Introductory Biostatistics

2.19 xs^2 s

Treatment 651.9 31,394.3 177.2

Control 656.1 505.1 22.5

2.20 (a)x¼ 169 :0, mean is lower than LA’s;s^2 ¼ 81 :5,s¼ 9 :0;(b)CV¼5%.

2.21 x¼ 2 :5,s^2 ¼ 9 :5,s¼ 3 :1.

2.22 Mean¼14.1, geometric mean¼10.3, median¼12.5.

2.23 Mean¼21.3, geometric mean¼10.6, median¼10.0.

2.24 Mean¼98.5, geometric mean¼93.4, median¼92.5.

2.25 xs^2

Bulimic 22.1 21.0

Healthy 29.7 42.1

Bulimic group has smaller mean and smaller variance.

2.26 xs^2 s Median

Drug A 133.9 503.8 22.4 130.0

Drug R 267.4 4449.0 66.7 253.0

2.27 (a) For survival time:

xs^2 s

AG positive 62.5 2954.3 54.4

AG negative 17.9 412.2 20.3

(b)For WBC:

x Geometric Mean Median

AG positive 29,073.5 12,471.9 10,000

AG negative 29,262.5 13,771.9 20,000

2.28 Measure Value

Pearson’s 0.931

Kendall’s 0.875

Spearman 0.963

2.29 Measure Men Women

Pearson’s 0.514 0.718

Kendall’s 0.282 0.714

Spearman 0.377 0.849

ANSWERS TO SELECTED EXERCISES 507