Jensen Tire & Auto is deciding whether to purchase a maintenance contract for its new computer wheel alignment and balancing machine. Managers feel that maintenance expense should be related to usage, and they collected the following information on weekly usage (hours) and annual maintenance expense (in hundreds of dollars). Weekly Usage (hours) Annual Maintenance Expense 13 17.0 10 22.0 20 30.0 28 37.0 32 47.0 17 30.5 24 32.5 31 39.0 40 51.5 38 40.0 (a) Develop a scatter chart with weekly usage hours as the independent variable. What does the scatter chart indicate about the relationship between weekly usage and annual maintenance expense (in hundreds of dollars)? The scatter chart indicates there may be no noticeable linear relationship between weekly usage and annual maintenance expense. The scatter chart indicates there may be a positive linear relationship between weekly usage and annual maintenance expense. The scatter chart indicates there may be a negative linear relationship between weekly usage and annual maintenance expense. (b) Use the data to develop an estimated regression equation that could be used to predict the annual maintenance expense in hundreds of dollars (y) for a given number of hours of weekly usage (x). What is the estimated regression model? (Round your numerical values to four decimal places.) ŷ10.5280+ 0.9534x (c) Test whether the regression parameter B is equal to zero at a 0.05 level of significance. Find the p-value. (Round your answer to four decimal places.) p-value = 0.0228 (d) How much of the variation in the sample values of annual maintenance expense (in %) does the model you estimated in part (b) explain? (Round your answer to one decimal place.) 85.6 % (e) If the maintenance contract costs $3,000 per year, would you recommend purchasing it? Why or why not? (Round your answers to two decimal places.) The mean weekly usage in our sample is 25.3 hours per week. The expected expense of a machine being used 25.3 hours per week is $ 3465 hundred. Since this expected expense is greater than the cost of the maintenance contract, the maintenance contract is advisable.