Question: National Paper Company must purchase a new machine for producing cardboard boxes. The company must choose between two machines. The machines produce equally quality, the decision will be made on the higher productivity of the output. The company has decided to use a “paired difference” experiment. The output for the machines and the operator are listed below.

1 2 3 4 5 6 7 8

Machine #1 53 60 58 48 46 54 62 49

Machine #2 50 55 56 44 45 50 57 47

a. Assuming normality, test to see if there is a difference in hourly outputs of the two machines. Use a two tailed, paired difference test. Let alpha = .05. ( Hint: Again, use Minitab. You will type the outputs for your two machines in the work sheet. Then, go to Stat, Basic Stat and under basic stat click on paired t and continue.)

b. Use your confidence interval on your Minitab output to compute the 95% confidence interval for the mean difference.