Exercise 8.6 reported heights (in mm) of 55.5, 60.3, 60.6, 62.1, 65.5, and 69.2 for six seedlings fourteen days after germination.
a. Using software or a calculator, verify that the 95% confidence interval for the population mean is (57.3, 67.1).
b. Name two things you could do to get a narrower interval than the one in part a.
c. Construct a 99% confidence interval. Why is it wider than the 95% interval?
d. On what assumptions is the interval in part a based? Explain how important each assumption is.