Management of a home appliance store would like to understand the growth pattern of the monthly sales of Blu-ray disc players over the past two years. Managers have recorded the relevant data in the file P14_33.xlsx.

a. Create a scatterplot for these data. Comment on the observed behavior of monthly sales at this store over time.

b. Estimate an appropriate regression equation to explain the variation of monthly sales over the given time period. Interpret the estimated regression coefficients.

c. Analyze the estimated equation’s residuals. Do they suggest that the regression equation is adequate? If not, return to part band revise your equation. Continue to revise the equation until the results are satisfactory.