How do I perform the following with the excel data file?

4. When Blanchard shows your previous regression to Tyler to make his case for c-store advertising, she flat-out rejects your analysis. She argues that you omitted an important variable, namely the average high temperature in a week. "As we all know," she says, "we advertise more during the warm weather periods in Marseille. So the seemingly large effect of advertising in your regression is not truly due to the positive impact of advertising but instead reflects the impact good weather has on driving and on the demand for gas and convenience items."

To address Tyler's criticism include temperature in your previous regression.

a. Compare your new regression (with three independent variables) to your previous regression. Does Tyler's criticism appear to be justified? Explain.

b. Drop all variables from your regression that do not meet Tyler's desired level of significance. Based on the resulting regression, does advertising appear to be profitable? Provide an estimate for the net impact of c-store advertising.

c. What needs to be true in order for the coefficients in your regression for c-store advertising to be profitable? Can you prove that advertising is profitable?

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