Question 1

Stepwise selection will always find the best regression model.

Accepted Answer

A) True 
 B)False

Question 2

If a decision maker wishes to develop a regression model in which the University Class Standing is a categorical variable with 5 possible levels of response,then he will need to include how many dummy variables?

Accepted Answer

A) 5 
B) 4 
C) 1 
D) 3 
A) 5 
B) 4 
C) 1 
D) 3

Question 3

The method used in regression analysis for incorporating a categorical variable into the model is by organizing the categorical variable into one or more dummy variables.

Accepted Answer

A) True 
 B)False

Question 4

The following residual plot is an output of a regression model.   Based on this residual plot,there is evidence to suggest that the underlying relationship between the y variable and the x variable is nonlinear.

Accepted Answer

A) True 
 B)False

Question 5

A regression equation that predicts the price of homes in thousands of dollars is   t = 24.6 + 0.055x1 - 3.6x2,where x2 is a dummy variable that represents whether the house in on a busy street or not.Here x2 = 1 means the house is on a busy street and x2 = 0 means it is not.Based on this information,which of the following statements is true?

Accepted Answer

A) On average,homes that are on busy streets are worth $3600 less than homes that are not on busy streets. 
B) On average,homes that are on busy streets are worth $3.6 less than homes that are not on busy streets. 
C) On average,homes that are on busy streets are worth $3600 more than homes that are not on busy streets. 
D) On average,homes that are on busy streets are worth $3.6 more than homes that are not on busy streets. 
A) On average,homes that are on busy streets are worth $3600 less than homes that are not on busy streets. 
B) On average,homes that are on busy streets are worth $3.6 less than homes that are not on busy streets. 
C) On average,homes that are on busy streets are worth $3600 more than homes that are not on busy streets. 
D) On average,homes that are on busy streets are worth $3.6 more than homes that are not on busy streets.

Question 6

If given a choice in collecting data on age for use as an independent variable in a regression model,a decision maker would generally prefer to record the actual age rather than an age category so as to avoid using dummy variables.

Accepted Answer

A) True 
 B)False

Question 7

If a stepwise regression approach is used to enter,one at a time,four variables into a regression model,the resulting regression equation may differ from the regression equation that occurs when all four of the variables are entered at one step.

Accepted Answer

A) True 
 B)False

Question 8

A regression model of the form:   = B0 + B1x1 + B2
 
   + B3
 
   + ε is called a 3rd order polynomial model.

Accepted Answer

A) True 
 B)False

Question 9

To determine the aptness of the model,which of the following would most likely be performed?

Accepted Answer

A) Check to see whether the residuals have a constant variance 
B) Determine whether the residuals are normally distributed 
C) Check to determine whether the regression model meets the assumption of linearity 
D) All of the above 
A) Check to see whether the residuals have a constant variance 
B) Determine whether the residuals are normally distributed 
C) Check to determine whether the regression model meets the assumption of linearity 
D) All of the above

Question 10

The following model: y = β0 + β1x1 + β2x2 + β3x1x2 + ε

Accepted Answer

A) is a linear model with interaction. 
B) is a second order polynomial model. 
C) is a composite model. 
D) is a convex model. 
A) is a linear model with interaction. 
B) is a second order polynomial model. 
C) is a composite model. 
D) is a convex model.

Question 11

The editors of a national automotive magazine recently studied 30 different automobiles sold in the United States with the intent of seeing whether they could develop a multiple regression model to explain the variation in highway miles per gallon.A number of different independent variables were collected.The following regression output (with some values missing)was recently presented to the editors by the magazine's analysts:   Based on this output and your understanding of multiple regression analysis,which of the independent variables is not considered statistically significant if the test is conducted at the 0.05 level of statistical significance?

Accepted Answer

A) All the variables in the model are statistically significant. 
B) None of the variables in the model is statistically significant. 
C) Torque and price as tested 
D) Cylinders,torque,and 0 to 60 
A) All the variables in the model are statistically significant. 
B) None of the variables in the model is statistically significant. 
C) Torque and price as tested 
D) Cylinders,torque,and 0 to 60

Question 12

Standard stepwise regression

Accepted Answer

A) is the same as forward selection. 
B) involves trying more regressions that the best subsets method. 
C) always finds the best regression model. 
D) combines attributes of both forward selection and backward elimination. 
A) is the same as forward selection. 
B) involves trying more regressions that the best subsets method. 
C) always finds the best regression model. 
D) combines attributes of both forward selection and backward elimination.

Question 13

A multiple regression is shown for a data set of yachts where the dependent variable is the price in thousands of dollars.   Based on this output,which of the independent variables appear to be significantly helping to predict the price of a yacht,using a 0.10 level of significance?

Accepted Answer

A) Age 
B) Age and length 
C) Rooms and Nav.Equip. 
D) Length and Nav.Equip. 
A) Age 
B) Age and length 
C) Rooms and Nav.Equip. 
D) Length and Nav.Equip.

Question 14

If the R-square for a multiple regression model with two independent variables is .64,the correlation between the two independent variables will be .80

Accepted Answer

A) True 
 B)False

Question 15

It is possible for the standard error of the estimate to actually increase if variables are added to the model that do not aid in explaining the variation in the dependent variable.

Accepted Answer

A) True 
 B)False

Question 16

The following regression output is from a multiple regression model:   The variables t,t2,and t3 represent the t,t-squared,and t-cubed respectively where t is the indicator of time from periods t = 1 to t = 20.Which of the following best describes the type of forecasting model that has been developed?

Accepted Answer

A) A complete third-order polynomial model 
B) A tri-variate smoothed regression model 
C) A nonlinear trend model 
D) A qualitative regression model 
A) A complete third-order polynomial model 
B) A tri-variate smoothed regression model 
C) A nonlinear trend model 
D) A qualitative regression model

Question 17

A study has recently been conducted by a major computer magazine publisher in which the objective was to develop a multiple regression model to explain the variation in price of personal computers.Three independent variables were used.The following computer printout shows the final output.However,several values are omitted from the printout.   Given this information,the regression model explains just under 70 percent of the variation in the price of personal computers.

Accepted Answer

A) True 
 B)False

Question 18

Second-order polynomial models:

Accepted Answer

A) always curve upward. 
B) always curve downward. 
C) can curve upward or downward depending on the data. 
D) measure interaction between variables. 
A) always curve upward. 
B) always curve downward. 
C) can curve upward or downward depending on the data. 
D) measure interaction between variables.

Question 19

In a multiple regression model,which of the following is true?

Accepted Answer

A) The coefficient of determination will be equal to the square of the highest correlation in the correlation matrix. 
B) Adding variables that have a low correlation with the dependent variable will cause the R-square value to decline. 
C) The sum of the residuals computed for the least squares regression equation will be zero. 
D) The adjusted R-square might be higher or lower than the value of the R-square. 
A) The coefficient of determination will be equal to the square of the highest correlation in the correlation matrix. 
B) Adding variables that have a low correlation with the dependent variable will cause the R-square value to decline. 
C) The sum of the residuals computed for the least squares regression equation will be zero. 
D) The adjusted R-square might be higher or lower than the value of the R-square.

Question 20

A major car magazine has recently collected data on 30 leading cars in the U.S.market.It is interested in building a multiple regression model to explain the variation in highway miles.The following correlation matrix has been computed from the data collected:
   The analysts also produced the following multiple regression output using curb weight,cylinders,and horsepower as the three independent variables.Note that a number of the output fields are missing,but can be determined from the information provided.   Based on the information provided,the three independent variables explain approximately 67 percent of the variation in the highway mileage among these 30 cars.

Accepted Answer

A) True 
 B)False

Stepwise selection will always find the best regression model.

If a decision maker wishes to develop a regression model in which the University Class Standing is a categorical variable with 5 possible levels of response,then he will need to include how many dummy variables?

The method used in regression analysis for incorporating a categorical variable into the model is by organizing the categorical variable into one or more dummy variables.

The following residual plot is an output of a regression model. Based on this residual plot,there is evidence to suggest that the underlying relationship between the y variable and the x variable is nonlinear.

If given a choice in collecting data on age for use as an independent variable in a regression model,a decision maker would generally prefer to record the actual age rather than an age category so as to avoid using dummy variables.

If a stepwise regression approach is used to enter,one at a time,four variables into a regression model,the resulting regression equation may differ from the regression equation that occurs when all four of the variables are entered at one step.

A regression model of the form: = B₀ + B₁x₁ + B₂ + B₃ + ε is called a 3^rd order polynomial model.

To determine the aptness of the model,which of the following would most likely be performed?

The following model: y = β₀+ β₁x₁+ β₂x₂+ β₃x₁x₂ + ε

Standard stepwise regression

A multiple regression is shown for a data set of yachts where the dependent variable is the price in thousands of dollars. Based on this output,which of the independent variables appear to be significantly helping to predict the price of a yacht,using a 0.10 level of significance?

If the R-square for a multiple regression model with two independent variables is .64,the correlation between the two independent variables will be .80

It is possible for the standard error of the estimate to actually increase if variables are added to the model that do not aid in explaining the variation in the dependent variable.

The following regression output is from a multiple regression model: The variables t,t2,and t3 represent the t,t-squared,and t-cubed respectively where t is the indicator of time from periods t = 1 to t = 20.Which of the following best describes the type of forecasting model that has been developed?

Second-order polynomial models:

In a multiple regression model,which of the following is true?

The Where,Why,and How of Data Collection

Graphs,Charts and Tablesdescribing Your Data

Describing Data Using Numerical Measures

Introduction to Probability

Discrete Probability Distributions

Introduction to Continuous Probability Distributions

Introduction to Sampling Distributions

Estimating Single Population Parameters

Introduction to Hypothesis Testing

Estimation and Hypothesis Testing for Two Population Parameters

Hypothesis Tests and Estimation for Population Variances

Analysis of Variance

Goodness-Of-Fit Tests and Contingency Analysis

Introduction to Linear Regression and Correlation Analysis

Analyzing and Forecasting Time-Series Data

Introduction to Nonparametric Statistics

Introduction to Quality and Statistical Process Control

Filters

Exam 15: Multiple Regression Analysis and Model Building

Stepwise selection will always find the best regression model.

If a decision maker wishes to develop a regression model in which the University Class Standing is a categorical variable with 5 possible levels of response,then he will need to include how many dummy variables?

The method used in regression analysis for incorporating a categorical variable into the model is by organizing the categorical variable into one or more dummy variables.

The following residual plot is an output of a regression model. Based on this residual plot,there is evidence to suggest that the underlying relationship between the y variable and the x variable is nonlinear.

If given a choice in collecting data on age for use as an independent variable in a regression model,a decision maker would generally prefer to record the actual age rather than an age category so as to avoid using dummy variables.

If a stepwise regression approach is used to enter,one at a time,four variables into a regression model,the resulting regression equation may differ from the regression equation that occurs when all four of the variables are entered at one step.

A regression model of the form: = B0 + B1x1 + B2 + B3 + ε is called a 3rd order polynomial model.

To determine the aptness of the model,which of the following would most likely be performed?

The following model: y = β0 + β1x1 + β2x2 + β3x1x2 + ε

Standard stepwise regression

A multiple regression is shown for a data set of yachts where the dependent variable is the price in thousands of dollars. Based on this output,which of the independent variables appear to be significantly helping to predict the price of a yacht,using a 0.10 level of significance?

If the R-square for a multiple regression model with two independent variables is .64,the correlation between the two independent variables will be .80

It is possible for the standard error of the estimate to actually increase if variables are added to the model that do not aid in explaining the variation in the dependent variable.

Second-order polynomial models:

In a multiple regression model,which of the following is true?

The Where,Why,and How of Data Collection

Graphs,Charts and Tablesdescribing Your Data

Describing Data Using Numerical Measures

Introduction to Probability

Discrete Probability Distributions

Introduction to Continuous Probability Distributions

Introduction to Sampling Distributions

Estimating Single Population Parameters

Introduction to Hypothesis Testing

Estimation and Hypothesis Testing for Two Population Parameters

Hypothesis Tests and Estimation for Population Variances

Analysis of Variance

Goodness-Of-Fit Tests and Contingency Analysis

Introduction to Linear Regression and Correlation Analysis

Analyzing and Forecasting Time-Series Data

Introduction to Nonparametric Statistics

Introduction to Quality and Statistical Process Control

Filters

A regression model of the form: = B₀ + B₁x₁ + B₂ + B₃ + ε is called a 3^rd order polynomial model.

The following model: y = β₀+ β₁x₁+ β₂x₂+ β₃x₁x₂ + ε