2.15 The following are the activity values (micromoles per minute per gram
of tissue) of a certain enzyme measured in the normal gastric tissue of 35
patients with gastric carcinoma:
0.360 1.189 0.614 0.788 0.273 2.464 0.571
1.827 0.537 0.374 0.449 0.262 0.448 0.971
0.372 0.898 0.411 0.348 1.925 0.550 0.622
0.610 0.319 0.406 0.413 0.767 0.385 0.674
0.521 0.603 0.533 0.662 1.177 0.307 1.499Calculate the meanx, variances^2 , and standard deviations.2.16 The data shown in Table 2.14 represent systolic blood pressure readings
on 15 women (see Example 2.9). Calculate the meanx, variances^2 , and
standard deviationsfor systolic blood pressure and for age.
2.17 The ages (in days) at time of death for samples of 11 girls and 16 boys
who died of sudden infant death syndrome are shown in Table E2.17.
Calculate the meanx, variances^2 , and standard deviationsfor each
group.
TABLE E2.17
Females Males
53 46 115
56 52 133
60 58 134
60 59 175
78 77 175
87 78
102 80
117 81
134 84
160 103
277 1142.18 A study was conducted to investigate whether oat bran cereal helps to
lower serum cholesterol in men with high cholesterol levels. Fourteen
men were placed randomly on a diet that included either oat bran or
cornflakes; after two weeks, their low-density lipoprotein (LDL) choles-
terol levels were recorded. Each man was then switched to the alternative
diet. After a second two-week period, the LDL cholesterol level of each
person was recorded again. The data are shown in Table E2.18. Calcu-
late the LDL di¤erence (cornflake—oat bran) for each of the 14 men,
then the meanx, variances^2 , and standard deviationsfor this sample of
di¤erences.
EXERCISES 97