Refer to “Medical Supply Company Case Study” computer printout posted at Module 1. The Medical Supply Company (MSC) is a chain of retail department stores in medical supply. The sales figures (both computer input and computer output) of the period 1996-2003 are shown in the computer printout. When t = 1 it means year 1996; when t = 2 it means year 1997; …; when t = 8 it means year 2003. Because the sales are in terms of dollars, the data are adjusted to reflect the changes in the value of dollars. Alternatively, sales can be shown in terms of units sold whenever possible, assuming that the units do not change much over time. The data are broken down into quarters. There are three dummy variables (X1, X2 and X3). What is a conclusion based on the F-test using a 5% level of significance?
Select one:a. We conclude that all of three dummy variables are needed in the multiple linear regression model.b. We conclude that only the Year is needed in the multiple linear regression model. c. We conclude that the Year and all of three dummy variables are needed in the multiple linear regression model. d. We conclude that the both Y-intercept and Year are needed in the multiple linear regression model. e. We conclude that none of the three dummy variables is needed in the multiple linear regression model.