DS 101 Version R082 – Sample Exam Questions
Simple Linear Regression Questions
1. In regression analysis, the model in the form is called
a. |
regression equation |
b. |
correlation equation |
c. |
estimated regression equation |
d. |
regression model |
2. The mathematical equation relating the independent variable to the expected value of the dependent variable; that is, E(y) = 0 + 1x, is known as
a. |
regression equation |
b. |
correlation equation |
c. |
estimated regression equation |
d. |
regression model |
3. The model developed from sample data that has the form of is known as
a. |
regression equation |
b. |
correlation equation |
c. |
estimated regression equation |
d. |
regression model |
4. In regression analysis, the unbiased estimate of the variance is
a. |
coefficient of correlation |
b. |
coefficient of determination |
c. |
mean square error |
d. |
slope of the regression equation |
5. The interval estimate of the mean value of y for a given value of x is
a. |
prediction interval estimate |
b. |
confidence interval estimate |
c. |
average regression |
d. |
x versus y correlation interval |
6. The standard error is the
a. |
t-statistic squared |
b. |
square root of SSE |
c. |
square root of SST |
d. |
square root of MSE |
7. If MSE is known, you can compute the
a. |
r square |
b. |
coefficient of determination |
c. |
standard error |
d. |
all of these alternatives are correct |
8. In regression analysis, which of the following is not a required assumption about the error term ?
a. |
The expected value of the error term is one. |
b. |
The variance of the error term is the same for all values of X. |
c. |
The values of the error term are independent. |
d. |
The error term is normally distributed. |
9. Larger values of r2 imply that the observations are more closely grouped about the
a. |
average value of the independent variables |
b. |
average value of the dependent variable |
c. |
least squares line |
d. |
origin |
10. In a regression and correlation analysis if r2 = 1, then
a. |
SSE must also be equal to one |
b. |
SSE must be equal to zero |
c. |
SSE can be any positive value |
d. |
SSE must be negative |
11. In a regression and correlation analysis if r2 = 1, then
a. |
SSE = SST |
b. |
SSE = 1 |
c. |
SSR = SSE |
d. |
SSR = SST |
12. The coefficient of correlation
a. |
is the square of the coefficient of determination |
b. |
is the square root of the coefficient of determination |
c. |
is the same as r-square |
d. |
can never be negative |
13. In regression analysis, if the independent variable is measured in pounds, the dependent variable
a. |
must also be in pounds |
b. |
must be in some unit of weight |
c. |
cannot be in pounds |
d. |
can be any units |
14. A regression analysis between sales (in $1000) and price (in dollars) resulted in the following equation
= 50,000 - 8X
The above equation implies that an
a. |
increase of $1 in price is associated with a decrease of $8 in sales |
b. |
increase of $8 in price is associated with an increase of $8,000 in sales |
c. |
increase of $1 in price is associated with a decrease of $42,000 in sales |
d. |
increase of $1 in price is associated with a decrease of $8000 in sales |
15. Regression analysis was applied between sales (in $1000) and advertising (in $100) and the following regression function was obtained.
= 500 + 4 X
Based on the above estimated regression line if advertising is $10,000, then the point estimate for sales (in dollars) is
a. |
$900 |
b. |
$900,000 |
c. |
$40,500 |
d. |
$505,000 |
Multiple Regression Questions
1. The mathematical equation relating the expected value of the dependent variable to the value of the independent variables, which has the form of E(y) = is
a. |
a simple linear regression model |
b. |
a multiple nonlinear regression model |
c. |
an estimated multiple regression equation |
d. |
a multiple regression equation |
2. The estimate of the multiple regression equation based on the sample data, which has the form of E(y) =
a. |
a simple linear regression model |
b. |
a multiple nonlinear regression model |
c. |
an estimated multiple regression equation |
d. |
a multiple regression equation |
3. The mathematical equation that explains how the dependent variable y is related to several independent variables x1, x2, ..., xp and the error term is
a. |
a simple nonlinear regression model |
b. |
a multiple regression model |
c. |
an estimated multiple regression equation |
d. |
a multiple regression equation |
4. A measure of the effect of an unusual x value on the regression results is called
a. |
Cook’s D |
b. |
Leverage |
c. |
odd ratio |
d. |
unusual regression |
5. In a multiple regression model, the error term is assumed to be a random variable with a mean of
a. |
zero |
b. |
-1 |
c. |
1 |
d. |
any value |
6. A regression model in which more than one independent variable is used to predict the dependent variable is called
a. |
a simple linear regression model |
b. |
a multiple regression model |
c. |
an independent model |
d. |
None of these alternatives is correct. |
7. A multiple regression model has the form
As x1 increases by 1 unit (holding x2 constant), y is expected to
a. |
increase by 9 units |
b. |
decrease by 9 units |
c. |
increase by 2 units |
d. |
decrease by 2 units |
8. A multiple regression model has the form
As X increases by 1 unit (holding W constant), Y is expected to
a. |
increase by 11 units |
b. |
decrease by 11 units |
c. |
increase by 6 units |
d. |
decrease by 6 units |
Exhibit 15-2
A regression model between sales (Y in $1,000), unit price (X1 in dollars) and television advertisement (X2 in dollars) resulted in the following function:
For this model SSR = 3500, SSE = 1500, and the sample size is 18.
9. Refer to Exhibit 15-2. The coefficient of the unit price indicates that if the unit price is
a. |
increased by $1 (holding advertising constant), sales are expected to increase by $3 |
b. |
decreased by $1 (holding advertising constant), sales are expected to decrease by $3 |
c. |
increased by $1 (holding advertising constant), sales are expected to increase by $4,000 |
d. |
increased by $1 (holding advertising constant), sales are expected to decrease by $3,000 |
10. Refer to Exhibit 15-2. The coefficient of X2 indicates that if television advertising is increased by $1 (holding the unit price constant), sales are expected to
a. |
increase by $5 |
b. |
increase by $12,000 |
c. |
increase by $5,000 |
d. |
decrease by $2,000 |
Exhibit 15-4
a.
b.
c.
d.
11. Which equation describes the multiple regression model?
a. |
Equation A |
b. |
Equation B |
c. |
Equation C |
d. |
Equation D |
12. Which equation gives the estimated regression line?
a. |
Equation A |
b. |
Equation B |
c. |
Equation C |
d. |
Equation D |
13. Which equation describes the multiple regression equation?
a. |
Equation A |
b. |
Equation B |
c. |
Equation C |
d. |
Equation D |
Exhibit 15-5
Below you are given a partial Minitab output based on a sample of 25 observations.
|
Coefficient |
Standard Error |
Constant |
145.321 |
48.682 |
X1 |
25.625 |
9.150 |
X2 |
-5.720 |
3.575 |
X3 |
0.823 |
0.183 |
14. Refer to Exhibit 15-5. The estimated regression equation is
a. |
|
b. |
|
c. |
|
d. |
|
15. Refer to Exhibit 15-5. The interpretation of the coefficient on X1 is that
a. |
a one unit change in X1 will lead to a 25.625 unit change in Y |
b. |
a one unit change in X1 will lead to a 25.625 unit increase in Y when all other variables are held constant |
c. |
a one unit change in X1 will lead to a 25.625 unit increase in X2 when all other variables are held constant |
d. |
It is impossible to interpret the coefficient. |
CLI SPECIAL DIRECTIVES PRINT CLI VERSION
der Universität Zürich (uzh) Version xx mai 2012
DIGIT EPREDMETI VERSION 10 01082008
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