During the recession that began in 2008, not only did some people stop making house payments, but they also stopped making payments for local government services such as trash collection and water and sewer services. The following data have been collected by an accountant who is performing an audit of account balances for a major city billing department. The population from which the data were collected represents those accounts for which the customer had indicated the balance was incorrect. The dependent variable,

y, is the actual account balance as verified by the accountant. The independent variable, x, is the computer-generated account balance.

x 233 10 24 56 78 102 90 200 344 120 18 y 245 12 22 56 90 103 85 190 320 120 23

a. Compute the least squares regression equation.

b. If the computer-generated account balance was 100, what would you expect to be the actual account balance as verified by the accountant?

c. The computer-generated balance for Timothy Jones is listed as 100 in the computer-generated account record. Calculate a 90% interval estimate for Mr. Joness actual account balance.

d. Calculate also a 90% interval estimate for the average of all customers actual account balances in which a computer-generated account balance is the same as that of Mr. Jones (part c). Interpret your results.