In a manufacturing process the assembly line speed (feet per minute) was thought to affect the number of defective parts found during the inspection process. To test this theory, managers devised a situation in which the same batch of parts was inspected visually at a variety of line speeds. They collected the following data.

a. Develop the estimated regression equation that relates line speed to the number of defective parts found.

b. At a .05 level of significance, determine whether line speed and number of defective parts found are related.

c. Did the estimated regression equation provide a good fit to the data?

d. Develop a 95% confidence interval to predict the mean number of defective parts for a line speed of 50 feet per minute.