Body Temperature. A study by researchers at the University of Maryland addressed the question of whether the mean body temperature of humans is 98.6◦F. The results of the study by P. Mackowiak et al. appeared in the article “A Critical Appraisal of 98.6◦F, the Upper Limit of the Normal Body Temperature, and Other Legacies of Carl Reinhold August Wunderlich” (Journal of the American Medical Association, Vol. 268, pp. 1578–1580). Among other data, the researchers obtained the body temperatures of 93 healthy humans, as provided on the WeissStats site. Use the technology of your choice to do the following.

a. Obtain a normal probability plot, boxplot, histogram, and stemand-leaf diagram of the data.

b. Based on your results from part (a), can you reasonably apply one-standard-deviation χ2-procedures to the data? Explain your reasoning.

c. In Exercise 9.91, you were asked to use these data to decide whether mean body temperature of healthy humans differs from 98.6◦F. There, you were to assume that the population standard deviation of body temperatures for healthy humans is 0.63◦F.

At the 5% significance level, do the data provide evidence against that assumption?

d. Find and interpret a 95% confidence interval for the population standard deviation of body temperatures for healthy humans.