Question: Gym Outfitters sells and services exercise equipment such as treadmills, ellipticals, and stair climbers to gymnasiums and recreational centers. The company's management would like to determine if there is a relationship between the number of minutes required to complete a routine service call and the number of machines serviced. A random sample of 12 records revealed the following information concerning the number of machines serviced and the time (in minutes) to complete the routine service call:
a. Estimate the least squares regression equation.
b. If a gymnasium had six machines, how many minutes should Gym Outfitters expect a routine service call to require?
c. Provide a 90% confidence interval for the average amount of time required to complete a routine service call when the number of machines being serviced is nine.
d. Provide a 90% prediction interval for the time required to complete a particular routine service call for a gymnasium that has seven machines.