Ashford University Week 4 Price of A Portrait Questions

Let Yt be the sales during month t (in thousands of dollars) for a photography studio, and let Pt be the price charged for portraits during month t. The data are in the file attached. Use regression to fit the following model to these data:

Yt = a + b1Yt−1 + b2Pt + et
This equation indicates that last month’s sales and the current month’s price are explanatory variables. The last term, et, is an error term.

1. If the price of a portrait during month 21 is $10, what would you predict for sales in month 21?
2. Does there appear to be a problem with autocorrelation of the residual? Explain your answer.