The lengths of life (in hours) of a sample of 40 100- watt light bulbs produced by Manufacturer A and a sample of 40 100-watt light bulbs produced by Manufacturer B are stored in Bulbs.
a. Using a 0.05 level of significance, is there evidence of a difference in the median life of bulbs produced by the two manufacturers?
b. What assumptions must you make in (a)?
c. Compare the results of (a) with those of Problem 10.66 (a) on page 402. Discuss.