Introductory Biostatistics

(a)Calculate separately for each group (AG positive and AG negative)

the meanx, variances^2 , and standard deviationsfor survival time.

(b)Calculate separately for each group (AG positive and AG negative)

the mean, geometric mean, and median for white blood count.

2.28 Refer to the data on systolic blood pressure (mmHg) of 12 women
in Exercise 2.21. Calculate Pearson’s correlation coe‰cient, Kendall’s
tau, and Spearman’s rho rank correlation coe‰cients representing the
strength of the relationship between systolic blood pressures measured
before and after administration of the oral contraceptive.

2.29 The following are the heights (measured to the nearest 2 cm) and weights
(measured to the nearest kilogram) of 10 men and 10 women. For the men,

Height 162 168 174 176 180 180 182 184 186 186

Weight 65 65 84 63 75 76 82 65 80 81

and for the women,

Height 152 156 158 160 162 162 164 164 166 166

Weight 52 50 47 48 52 55 55 56 60 60

(a)Draw a scatter diagram, for men and women separately, to show the

association, if any, between height and weight.

(b)Calculate Pearson’s correlation coe‰cient, Kendall’s tau, and

Spearman’s rho rank correlation coe‰cients of height and weight for

men and women separately.

2.30 Table E2.30 gives the net food supply (x, the number of calories per
person per day) and the infant mortality rate (y, the number of infant

TABLE E2.30

Country xyCountry xy

Argentina 2730 98.8 Iceland 3160 42.4

Australia 3300 39.1 India 1970 161.6

Austria 2990 87.4 Ireland 3390 69.6

Belgium 3000 83.1 Italy 2510 102.7

Burma 1080 202.1 Japan 2180 60.6

Canada 3070 67.4 Netherlands 3010 37.4

Chile 2240 240.8 New Zealand 3260 32.2

Cuba 2610 116.8 Sweden 3210 43.3

Egypt 2450 162.9 U.K. 3100 55.3

France 2880 66.1 U.S. 3150 53.2

Germany 2960 63.3 Uruguay 2380 94.1

102 DESCRIPTIVE METHODS FOR CONTINUOUS DATA