Question

1. The overall regression F-statistic tests the null hypothesis that:

A) all slope coefficients are zero.

B) all slope coefficients and the intercept are zero.

C) the intercept in the regression and at least one, but not all, of the slope coefficients is zero.

D) the slope coefficient of the variable of interest is zero, but that the other slope coefficients are not.

2. Consider the following model: .

Yield is measured in tons per acre and rainfall is measured in liters. Answer the questions:

What would happen to the value of β1 and of β2 if yield were to be measured in kilograms (kg) per acre instead of tons (1 ton = 1,000 kg). Rainfall is still measured in liters.

Answer 1

1. The overall regression F-statistics tests the null hypothesis that all the slope coefficients are zero. In other words the model has no predictive capability, basically F-test compares the model with zero predictor variables (intercept model).

Hence, answer is A (all slope coefficients are zero)

2. Consider the model where Yield is dependent variable and Rainfall as predictor. Here, the Y is measured in tons per acre and X in liters. Now if we change the Y's unit to kg (1tons = 1000kg), there would not be any change in the Beta's.