Your company provides computers, printers, and Internet service to a number of engineers and programmers so that they can telecommute from home.

Because of the cost of name-brand printer replacement cartridges, several companies have entered the secondary market. You are currently considering offers from four companies. The prices are equivalent, so you will make your decision based on number of pages printed. You have given samples of four cartridges to 16 programmers and engineers and have received the following numbers of pages:

Supplier A Supplier B Supplier C Supplier D 424 650 521 323 521 725 601 383 650 826 590 487 422 722 522 521

a. Using a significance level equal to 0.01, what conclusion should you reach about the four manufacturers’ printer cartridges? Explain.

b. If the test conducted in part a reveals that you should reject the null hypothesis, which supplier should you choose? Is there one or more you can eliminate based on these data? Use the appropriate test for multiple comparisons. Discuss.