53. Nine Australian soldiers were subjected to extreme conditions, which involved a 100-minutewalk with a 25-lb pack when the temperature was 40C (104F).

One of them overheated (above 39C) and was removed from the study. Here are the rectal Celsius temperatures of the other eight at the end of the walk

( Neural Network Training on Human Body Core Temperature Data, Combatant Protection and Nutrition Branch, Aeronautical and Maritime Research Laboratory of Australia, DSTO TN-0241, 1999):

38.4 38.7 39.0 38.5 38.5 39.0 38.5 38.6 We would like to get a 95% con dence interval for the population mean.

a. Compute the t-based con dence interval of Section 8.3.

b. Check for the validity of part (a).

c. Generate a bootstrap sample of 1000 means.

d. Use the standard deviation for part

(c) to get a 95% con dence interval for the population mean.

e. Investigate the distribution of the bootstrap means to see if part

(d) is valid.

f. Use part

(c) to form the 95% con dence interval using the percentile method.

g. Compare the intervals and explain your preference.

h. Based on your knowledge of normal body temperature, would you say that body temperature can be in uenced by environment?