1. The data set calcium .txt contains the calcium levels of eleven test sub jects at zero hours and three hours after taking a multi-vitamin containing calcium.
(a) Make the appropriate normal probability plot and comment on it.
(b) Is there any evidence that calcium levels are affected by this vitamin? Test, using a = 0.10.
(c) Construct a 90% confidence interval for the mean difference in calcium levels.
(d) Write a short report on the experiment and its results.
2. The data set yellow .txt contains yellowing data ( b is a color measure) for 23 samples of monomer used in the casting of optical lenses. The data include an initial measurement and a measurement after 1 month of storage. It is hoped that the material is stable and that the yellowing value does not change over time.
(a) Calculate the pairwise differences (initial - 1month) and find the mean and standard deviation of the differences.
(b) Make a normal probability plot of the differences and explain what it indicates.
(c) Find a 95% confidence interval for the average difference in yellowing values. Explain what the confidence interval means.