Biological effects of magnetic fields are a matter of current concern and research. In a...

Biological effects of magnetic fields are a matter of current concern and research. In an early study of the effects of a strong magnetic field on the development of mice (Barnothy 1964), 10 cages, each containing three 30-day-old albino female mice, were subjected for a period of 12 days to a field with an average strength of 80 Oe/cm. Thirty other mice housed in 10 similar cages were not placed in a magnetic field and served as controls. The following table shows the weight gains, in grams, for each of the cages.

a. Display the data graphically with parallel dotplots. (Draw two parallel number lines and put dots on one corresponding to the weight gains of the controls and on the other at points corresponding to the gains of the treatment group.)

b. Find a 95% confidence interval for the difference of the mean weight gains.

c. Use a t test to assess the statistical significance of the observed difference. What is the p-value of the test?

d. Repeat using a nonparametric test.

e. What is the difference of the median weight gains?

f. Use the bootstrap to estimate the standard error of the difference of median weight gains.

g. Form a confidence interval for the difference of median weight gains based on the bootstrap approximation to the sampling distribution.