Question 1

In a multiple regression analysis, if the normal probability plot ________, then it can be concluded that the assumption of normality is not violated.

Accepted Answer

A)  is a straight line 
B)  has the shape of a symmetric bell-shaped curve 
C)  is greatly curved 
D)  is left skewed 
E)  has the shape of a parabola that opens upward 
A)  is a straight line 
B)  has the shape of a symmetric bell-shaped curve 
C)  is greatly curved 
D)  is left skewed 
E)  has the shape of a parabola that opens upward A

Question 2

Which of the following is not an assumption of the multiple linear regression model?

Accepted Answer

A)  The error terms are independent. 
B)  The population of error terms has a normal distribution. 
C)  Populations of error terms observed at different combinations of values of the independent variable (x1, x2,. . ., xk) have equal variances. 
D)  The level of measurement of the data for the dependent variable is at least ordinal. 
E)  At any combination of values of x1, x2, . . . , xk, the population of potential error term values has a mean equal to zero. 
A)  The error terms are independent. 
B)  The population of error terms has a normal distribution. 
C)  Populations of error terms observed at different combinations of values of the independent variable (x1, x2,. . ., xk) have equal variances. 
D)  The level of measurement of the data for the dependent variable is at least ordinal. 
E)  At any combination of values of x1, x2, . . . , xk, the population of potential error term values has a mean equal to zero. D

Question 3

Stepwise regression uses a series of ________ tests during each iteration in order to determine which independent variables should be brought into the regression model.

Accepted Answer

A)  C 
B)  chi-square 
C)  t or F 
D)  VIF 
A)  C 
B)  chi-square 
C)  t or F 
D)  VIF C

Question 4

The assumption of independent error terms in regression analysis is often violated when using time-series data.

Accepted Answer

A) True 
 B)False

Question 5

If we are predicting y when the values of the independent variables are x01, x02, . . . , x0k, the farther the values of x01, x02, . . . , x0k are from the center of the observed data, the smaller the distance value and the more precise the associated confidence and prediction intervals.

Accepted Answer

A) True 
 B)False

Question 6

When the F test is used to test the overall significance of a multiple regression model, if the null hypothesis is rejected, it can be concluded that all of the independent variables   are significantly related to the dependent variable y.

Accepted Answer

A) True 
 B)False

Question 7

In multiple regression analysis, which one of the following is the appropriate notation for error, or residual?

Accepted Answer

A)    −
  
B)    −
  
C)    −
  
D)    −
  
E)  None of these answers is correct. 
A)    −
  
B)    −
  
C)    −
  
D)    −
  
E)  None of these answers is correct.

Question 8

Backward elimination regression is an automatic model-building procedure.

Accepted Answer

A) True 
 B)False

Question 9

In using a regression model, if a new independent variable is added, the value of R2 (the coefficient of multiple determination) will ________ decrease.

Accepted Answer

A)  always 
B)  sometimes 
C)  never 
A)  always 
B)  sometimes 
C)  never

Question 10

In using the multiple regression method, we can model the effects of the different levels of a qualitative independent variable by using a(n) ________.

Accepted Answer

A)  interaction variable 
B)  cross-product term 
C)  quadratic term 
D)  dummy (indicator) variable 
E)  variance equalizing transformation 
A)  interaction variable 
B)  cross-product term 
C)  quadratic term 
D)  dummy (indicator) variable 
E)  variance equalizing transformation

Question 11

In a multiple regression model, the residuals were plotted against the values of one of the independent variables. The plot exhibited a funneling out pattern of residuals. This means that as the value of the independent variable increases, the error terms tend to ________ and the model assumption of ________ is violated.

Accepted Answer

A)  increase, constant variance 
B)  increase, independence 
C)  decrease, constant variance 
D)  decrease, normality 
A)  increase, constant variance 
B)  increase, independence 
C)  decrease, constant variance 
D)  decrease, normality

Question 12

The multiple correlation coefficient can assume any value between zero and 1, inclusive.

Accepted Answer

A) True 
 B)False

Question 13

In regression analysis, the standard error(s) is ________ greater than the standard deviation of y, the dependent variable.

Accepted Answer

A)  always 
B)  sometimes 
C)  never 
A)  always 
B)  sometimes 
C)  never

Question 14

R2 is defined as

Accepted Answer

A)  total variation/explained variation. 
B)  explained variation/total variation. 
C)  unexplained variation/explained variation. 
D)  unexplained variation/total variation. 
A)  total variation/explained variation. 
B)  explained variation/total variation. 
C)  unexplained variation/explained variation. 
D)  unexplained variation/total variation.

Question 15

An investigator hired by a client suing for sex discrimination has developed a multiple regression model for employee salaries for the company in question. In this multiple regression model, the salaries are in thousands of dollars. For example, a data entry of 35 for the dependent variable indicates a salary of $35,000. The indicator (dummy) variable for gender is coded as X1 = 0 if male and X1 = 1 if female. The computer output of this multiple regression model shows that the coefficient for this variable (X1) is −4.2. The t test showed that X1 was significant at α = .1. This result implies that for male and female workers of the company,

Accepted Answer

A)  on the average, females earn $4,200 less than males. 
B)  on the average, males earn $4,200 less than females. 
C)  on the average, salaries do not differ between males and females. 
D)  on the average, males have 4.2 more years of experience than females. 
E)  on the average, females have 4.2 more years of experience than males. 
A)  on the average, females earn $4,200 less than males. 
B)  on the average, males earn $4,200 less than females. 
C)  on the average, salaries do not differ between males and females. 
D)  on the average, males have 4.2 more years of experience than females. 
E)  on the average, females have 4.2 more years of experience than males.

Question 16

It is appropriate to use an interaction variable if the relationship between the dependent variable and one of the independent variables depends on the value of the other independent variable.

Accepted Answer

A) True 
 B)False

Question 17

The multiple coefficient of determination is the ________ divided by the total variation.

Accepted Answer

A)  unexplained variation 
B)  SSE 
C)  explained variation 
D)  distance value 
E)  leverage value 
A)  unexplained variation 
B)  SSE 
C)  explained variation 
D)  distance value 
E)  leverage value

Question 18

Dummy variables take on the values of ________ and are used to model the effects of different levels of qualitative variables.

Accepted Answer

A)  1 or −1 
B)  1 or 2 
C)  0 or 2 
D)  0 or 1 
A)  1 or −1 
B)  1 or 2 
C)  0 or 2 
D)  0 or 1

Question 19

Multicollinearity is severe if the largest variance inflation factor (VIF) is greater than ________.

Accepted Answer

A)  100 
B)  5 
C)  10 
D)  1 
A)  100 
B)  5 
C)  10 
D)  1

Question 20

Adding any independent variable to a regression model will increase ________.

Accepted Answer

A)  adjusted R2 or R−2 
B)  s 
C)  MSE 
D)  R2 
E)  the length of all prediction intervals 
A)  adjusted R2 or R−2 
B)  s 
C)  MSE 
D)  R2 
E)  the length of all prediction intervals

In a multiple regression analysis, if the normal probability plot ________, then it can be concluded that the assumption of normality is not violated.

Which of the following is not an assumption of the multiple linear regression model?

Stepwise regression uses a series of ________ tests during each iteration in order to determine which independent variables should be brought into the regression model.

The assumption of independent error terms in regression analysis is often violated when using time-series data.

When the F test is used to test the overall significance of a multiple regression model, if the null hypothesis is rejected, it can be concluded that all of the independent variables are significantly related to the dependent variable y.

In multiple regression analysis, which one of the following is the appropriate notation for error, or residual?

Backward elimination regression is an automatic model-building procedure.

In using a regression model, if a new independent variable is added, the value of R² (the coefficient of multiple determination) will ________ decrease.

In using the multiple regression method, we can model the effects of the different levels of a qualitative independent variable by using a(n) ________.

The multiple correlation coefficient can assume any value between zero and 1, inclusive.

In regression analysis, the standard error(s) is ________ greater than the standard deviation of y, the dependent variable.

R² is defined as

It is appropriate to use an interaction variable if the relationship between the dependent variable and one of the independent variables depends on the value of the other independent variable.

The multiple coefficient of determination is the ________ divided by the total variation.

Dummy variables take on the values of ________ and are used to model the effects of different levels of qualitative variables.

Multicollinearity is severe if the largest variance inflation factor (VIF) is greater than ________.

Adding any independent variable to a regression model will increase ________.

An Introduction to Business Statistics and Analytics

Descriptive Statistics and Analytics: Tabular and Graphical Methods

Descriptive Statistics and Analytics: Numerical Methods

Probability and Probability Models

Predictive Analytics I: Trees, K-Nearest Neighbors, Naive Bayes,

Discrete Random Variables

Continuous Random Variables

Sampling Distributions

Confidence Intervals

Hypothesis Testing

Statistical Inferences Based on Two Samples

Experimental Design and Analysis of Variance

Chi-Square Tests

Simple Linear Regression Analysis

Predictive Analytics Ii: Logistic Regression, Discriminate Analysis,

Time Series Forecasting and Index Numbers

Nonparametric Methods

Decision Theory

Filters

Exam 15: Multiple Regression and Model Building

In a multiple regression analysis, if the normal probability plot ________, then it can be concluded that the assumption of normality is not violated.

Which of the following is not an assumption of the multiple linear regression model?

Stepwise regression uses a series of ________ tests during each iteration in order to determine which independent variables should be brought into the regression model.

The assumption of independent error terms in regression analysis is often violated when using time-series data.

If we are predicting y when the values of the independent variables are x01, x02, . . . , x0k, the farther the values of x01, x02, . . . , x0k are from the center of the observed data, the smaller the distance value and the more precise the associated confidence and prediction intervals.

When the F test is used to test the overall significance of a multiple regression model, if the null hypothesis is rejected, it can be concluded that all of the independent variables are significantly related to the dependent variable y.

In multiple regression analysis, which one of the following is the appropriate notation for error, or residual?

Backward elimination regression is an automatic model-building procedure.

In using a regression model, if a new independent variable is added, the value of R2 (the coefficient of multiple determination) will ________ decrease.

In using the multiple regression method, we can model the effects of the different levels of a qualitative independent variable by using a(n) ________.

The multiple correlation coefficient can assume any value between zero and 1, inclusive.

In regression analysis, the standard error(s) is ________ greater than the standard deviation of y, the dependent variable.

R2 is defined as

It is appropriate to use an interaction variable if the relationship between the dependent variable and one of the independent variables depends on the value of the other independent variable.

The multiple coefficient of determination is the ________ divided by the total variation.

Dummy variables take on the values of ________ and are used to model the effects of different levels of qualitative variables.

Multicollinearity is severe if the largest variance inflation factor (VIF) is greater than ________.

Adding any independent variable to a regression model will increase ________.

An Introduction to Business Statistics and Analytics

Descriptive Statistics and Analytics: Tabular and Graphical Methods

Descriptive Statistics and Analytics: Numerical Methods

Probability and Probability Models

Predictive Analytics I: Trees, K-Nearest Neighbors, Naive Bayes,

Discrete Random Variables

Continuous Random Variables

Sampling Distributions

Confidence Intervals

Hypothesis Testing

Statistical Inferences Based on Two Samples

Experimental Design and Analysis of Variance

Chi-Square Tests

Simple Linear Regression Analysis

Predictive Analytics Ii: Logistic Regression, Discriminate Analysis,

Time Series Forecasting and Index Numbers

Nonparametric Methods

Decision Theory

Filters

In using a regression model, if a new independent variable is added, the value of R² (the coefficient of multiple determination) will ________ decrease.

R² is defined as