Problem 1 An electric utility is interested in developing a model relating peak-hour demand (y in kilowatts) to total monthly energy usage during the month (x, in kilowatt hours). Data for 50 residential customers are available in the file sheet electric. a. Draw a scatter diagram of y versus x. b. Fit the simple linear regression model. c. Test for significance of regression using a = 0.05. d. Plot the residuals versus yi and comment on the underlying regression assumptions. Specifically, does it seem that the equality of variance assumption is satisfied