A Regression Model Relating Units Sold (Y), Price (X₁), and Whether

Essay

A regression model relating units sold (y), price (x₁), and whether or not promotion for sales was used (x₂ = 1 if promotion was used and 0 if not) resulted in the following estimated equation. $\hat { y }$ = 120 - .03x₁ + .7x₂
and the following information is also provided. $n = 15 \quad s b _ { 1 } = .01 \quad s b _ { 2 } = .10$ ​
a.
Is price a significant variable? Let α = .05.
b.
Is promotion significant? Let α = .05.