If x1 30oc and x2 80 what is the predicted value of y if

Question

Question - Understanding the fitted regression line. Researchers study the rate of water loss (% body weight per minute) of a tropical bedbug exposed to different combinations of temperature x₁ and relative humidity x₂. The fitted regression equation for their multiple regression is y^{^} = -2.7 + 0.05x₁ + 0.04x₂

(a) If x¹ = 30^oC and x² = 80%, what is the predicted value of y?

(b) For the answer to part (a) to be valid, is it necessary that the values x¹ = 30 and x² = 80 correspond to a case in the data set? Explain why or why not.

(c) If you hold x² at a fixed value, what is the effect of an increase of 5^oC on the predicted value of y?