Using 50 observations, the following regression output is obtained from estimating y = 0 + 1 x + 2 d 1 +

Using 50 observations, the following regression output is obtained from estimating y = β₀ + β₁x + β₂d₁ + β₃d₂ + .

a. Compute y̅ for x = 250, d₁ = 1 and d₂ = 0; then compute y̅ for x = 250, d₁ = 0 and d₂ = 1.

b. Interpret d₁ and d₂. Are both dummy variables individually significant at the 5% level? Explain.

Standard Coefficients Error tStat p-value Intercept -0.61 0.23 -2.75 0.0074 3.12 1.04 3.01 0.0034 -13.22 15.65 -0.85 0.4006 da 5.35 1.25 4.27 0.0000