Given: Stalk Heighti = 2.0 + 3.0 Rainfalli + 4.0 Fertilizeri + ei where Stalk Height is the average height of corn stalks in a field Rainfall is average rainfall per week on the field Fertilizer is the amount of fertilizer applied to the field

(A) Interpret the value of the intercept.

(B) Interpret the value of the coefficient on Rainfall.

(C) Suppose you were told that the true value of the coefficient on Rainfall is 3.1. Does this mean the estimate above is biased?

Explain.

(D) Suppose you were told that the equation does not meet assumption 2 of the CLRM (The error term has a zero population mean.) Does this mean that the coefficient on Rainfall is definitely not 3.0? Explain.

(E) When the data for this regression were gathered, Fertilizer was carefully applied to the various plots of corn so that each plot received exactly 2 lbs/acre of fertilizer more than the previous plot. Rainfall was measured using “dip canisters” in the standard meteorological way. Which of these explanatory variables is fixed? Explain.
(F) Since one of the explanatory variables is not predetermined, why is it still possible that the estimators of this regression are linear?