1. A multiple regression model has:

a. only one independent variable.

b. only two independent variables.

c. more than one dependent variable.

d. more than one independent variable.

2. To test the validity of a multiple regression model, we test the null hypothesis that the regression coefficients are all zero by applying the:

a. F-test

b. t-test

c. z-test

d. None of these choices.

3. If all the points for a multiple regression model with two independent variables were right on the regression plane, then the coefficient of determination would equal:

a. 0.

b. 1.

c. 2, since there are two independent variables.

d. None of these choices.

4. In a multiple regression model, the error variable is assumed to have a mean of:

a. 1.0

b. 0.0

c. 1.0

d. None of these choices

5. A multiple regression model has the form: =5.25+2x1+6x2 . As x2 increases by one unit, holding x1 constant, then the value of y will increase by:

a. 7.25 units.

b. 6 units on average.

c. 2 units.

d. 6 units.

8. In a multiple regression model, the value of the coefficient of determination has to fall between

a. 1 and +1.

b. 0 and +1.

c. 1 and 0.

d. None of these choices

Give a brief explanation for each question.