A marketing executive is studying online services, and is researching the effect of web page hits, advertising budget, and price on a service’s number of subscriptions. A sample of 25 online services is collected. The variable definitions and an overview of the data follow.

a. Conduct a regression analysis using all independent variables. Report the regression equation.b. Conduct a global test of hypothesis to determine whether any of the regression coefficients are not equal to zero.c. Conduct a test for the individual coefficients. Would you consider deleting any coefficients?d. Determine the residuals and plot them against the fitted values. Do you see any problems?e. Develop a histogram of the residuals. Do you see any problems with the normality assumption?

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Sub Number of subscriptions (in thousands) Web page hits = Average monthly count (in thousands) Adv = The advertising budget of the service (in $ hundreds) Price = Average monthly subscription price ($) Service Sub 1 2 3 ... 3 w 23 24 25 Adv Price 37.95 588.9 $13.2 $35.1 585.3 34.7 566.3 34.8 Web Page Hits 37.66 37.55 13.2 19.8 : 22.0 38.83 629.6 35.3 38.33 680.0 24.2 34.7 40.24 651.2 33.0 35.8