3. A study was made by a retail merchant to determine the relation between weekly advertising expenditures and sales. The correlation is 0.635 (Enter your answers in three decimal places) Summary Statistics Variable Mean Std Dexr Advertising Costs 34.5 29.5 Sales 407.5 50.9 [a)To predict the weekly sales from advertising costs, what is the slope b? (Enter your answers in three decimal places) 1.095 V (b) To predict the weekly sales from advertising costs, what ls the y-intercept a? (Enter your answers in two decimal places) 403.30 x (c) Estimate the weekly sales when advertising costs are $35? (Enter your answers in two decimal places) _1717 x )How many percent of variation in advertising cost can be explained by sales' In regression line? [ For example, 25.4% enter 25; 25.5% enter 26) _x