The Following Regression Model Has Been Proposed to Predict Monthly $\hat { Y }$

Short Answer

The following regression model has been proposed to predict monthly sales at a shoe store.
$\hat { Y }$ = 40 - 3X1 + 12X2 + 10X3
where
X1 = competitor's previous month's sales in $1,000s) X2 = store's previous month's sales in $1,000s)
X3 =
= sales in $1,000s)
$\hat { Y }$
a. Predict sales in dollars) for the shoe store if the competitor's previous month's sales were
$9,000, the store's previous month's sales were $30,000, and no radio advertisements were run.
b. Predict sales in dollars) for the shoe store if the competitor's previous month's sales were
$9,000, the store's previous month's sales were $30,000, and 10 radio advertisements were run.