Akiko Hamaguchi is a manager at a small sushi restaurant in Phoenix, Arizona. Akiko is concerned that the weak economic environment has hampered foot traffic in her area, thus causing a dramatic decline in sales. In order to offset the decline in sales, she has pursued a strong advertising campaign. She believes advertising expenditures have a positive influence on sales. To support her claim, Akiko estimates the following linear regression model: Sales = β0 + β1Unemployment + β2Advertising + . A portion of the regression results is shown in the accompanying table.

a. At the 5% significance level, test whether the explanatory variables jointly influence sales.
b. At the 1% significance level, test whether the unemployment rate is negatively related with sales.
c. At the 1% significance level, test whether advertising expenditures are positively related withsales.

ANOVA Regression Residual Total df MS F Significance F 272.6374 36.3187 8.7600.0034 14 6 130.681 58.0438 4.1460 Lower Upper Coeficients Eror tStatpwlue 95969596 17.50603.9817 4.3966 0.0006 8.97 26.05 Unemployment-0.6879 0.2997 2.2955 0.037733 0.05 0.02660.0068 3.9322 0.0015 0.01 0.04 Standard Intercept Advertising