Question 1

Which of the following regression output values is used in computing the variance inflation factors?

Accepted Answer

A) The standard error of the estimate 
B) The regression intercept value 
C) The F critical value from the F distribution for the appropriate number of degrees of freedom and the appropriate level of significance 
D) The R-squared value

Question 2

Consider the following regression model:  = B0 + B1x1 + B1
 
  + ε.If B2 > 0,then the parabola will open downward and if B2 < 0,then the parabola will open downward.

Accepted Answer

A) True 
 B)False

Question 3

A dummy variable is a dependent variable whose value is set at either zero or one.

Accepted Answer

A) True 
 B)False

Question 4

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 is the result of using a forward selection stepwise regression approach.  Which of the following might explain why no other independent variables entered the model?

Accepted Answer

A) No other variable had a correlation with the dependent variable that was close to 1.0. 
B) None of the remaining variables had a positive correlation with y. 
C) The remaining variables must be nearly perfectly correlated with the two variables already in the model. 
D) Given the two variables already in the model,none of the others could add significantly to the percentage of variation in the y variable that would be explained by the model.

Question 5

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,a number of the output fields are missing,but can be determined from the information provided.  Based on the above information,the test statistic for testing whether the overall model is statistically significant is approximately F = 17.4

Accepted Answer

A) True 
 B)False

Question 6

The multiple coefficient of determination measures the percentage of variation in the dependent variable that is explained by the independent variables in the model.

Accepted Answer

A) True 
 B)False

Question 7

In a multiple regression model where three independent variables are included in the model,the percentage of explained variation will be equal to the square of the sum of the correlations between the independent variables and the dependent variable.

Accepted Answer

A) True 
 B)False

Question 8

The correlation matrix is an effective means of determining whether any of the independent variables has a curvilinear relationship with the dependent variable.

Accepted Answer

A) True 
 B)False

Question 9

In the best subsets approach to regression analysis,if we start with 4 independent variables,a total of 33 different regression models will actually be computed for possible selection as the best model to use.

Accepted Answer

A) True 
 B)False

Question 10

A multiple regression was conducted to predict the price of yachts in thousands of dollars.A dummy variable was included to indicate whether or not the yacht has a flying bridge,where 0 means "no" and 1 means "yes."  Which of the following statements is correct using the 0.10 level of significance?

Accepted Answer

A) Having a flying bridge significantly increases the price of a yacht by an average of $17.7,given the other variables present. 
B) Having a flying bridge significantly increases the price of a yacht by an average of $17,708,given the other variables present. 
C) We can tell that 17 out of 20 yachts have a flying bridge. 
D) Whether or not the yacht has a flying bridge does not significantly affect the price of a yacht,given the other variables present.

Question 11

The multiple coefficient of determination is the average of all the squared correlations of the independent variables.

Accepted Answer

A) True 
 B)False

Question 12

Which of the following statements is true?

Accepted Answer

A) Dummy variables are used to incorporate categorical variables into a regression model. 
B) You should use one fewer dummy variables than are categories for the qualitative variable in question. 
C) It is appropriate to compute a correlation coefficient for the relationship between a dependent variable and a dummy variable. 
D) All of the above are true.

Question 13

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,a number of the output fields are missing,but can be determined from the information provided.  Based on the information provided,the 95 percent confidence interval estimate for regression slope coefficient for horsepower is approximately - 0.041 to 0.009 and since this interval crosses zero,we are unable to conclude that the regression slope coefficient for this variable is different from zero.

Accepted Answer

A) True 
 B)False

Question 14

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,using an alpha = .05 level,you can conclude that the overall regression model is statistically significant.

Accepted Answer

A) True 
 B)False

Question 15

Where there are two independent variables in a multiple regression,the regression equation forms a plane.

Accepted Answer

A) True 
 B)False

Question 16

You should not include more than one categorical variable in a multiple regression because the use of two or more will cause misleading results.

Accepted Answer

A) True 
 B)False

Question 17

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.Included in these were two variables described as follows:  If these two variables are to be included in a regression model,how many additional variables will be needed?

Accepted Answer

A) The model explains nearly 63 percent of the variation in the dependent variable. 
B) If tested at the 0.05 significance level,the overall model would be considered statistically significant. 
C) The variable X1 has a slope coefficient that is significantly different from zero if tested at the 0.05 level of significance. 
D) All of the above are true.

Question 18

In conducting multiple regression analysis,t-tests should be conducted prior to conducting the F-test.

Accepted Answer

A) True 
 B)False

Question 19

In simple linear regression analysis,the regression model forms a straight line in two-dimensional space through the x,y data points,while a multiple regression model forms a plane through multidimensional space.

Accepted Answer

A) True 
 B)False

Question 20

To describe variable credit status that has three levels: Excellent,Good,and Poor,we need to use two different dummy variables.

Accepted Answer

A) True 
 B)False

Exam 15: Multiple Regression Analysis and Model Building

Which of the following regression output values is used in computing the variance inflation factors?

Consider the following regression model: = B₀ + B₁x₁ + B₁ + ε.If B₂ > 0,then the parabola will open downward and if B₂ < 0,then the parabola will open downward.

A dummy variable is a dependent variable whose value is set at either zero or one.

The multiple coefficient of determination measures the percentage of variation in the dependent variable that is explained by the independent variables in the model.

In a multiple regression model where three independent variables are included in the model,the percentage of explained variation will be equal to the square of the sum of the correlations between the independent variables and the dependent variable.

The correlation matrix is an effective means of determining whether any of the independent variables has a curvilinear relationship with the dependent variable.

In the best subsets approach to regression analysis,if we start with 4 independent variables,a total of 33 different regression models will actually be computed for possible selection as the best model to use.

A multiple regression was conducted to predict the price of yachts in thousands of dollars.A dummy variable was included to indicate whether or not the yacht has a flying bridge,where 0 means "no" and 1 means "yes." Which of the following statements is correct using the 0.10 level of significance?

The multiple coefficient of determination is the average of all the squared correlations of the independent variables.

Which of the following statements is true?

Where there are two independent variables in a multiple regression,the regression equation forms a plane.

You should not include more than one categorical variable in a multiple regression because the use of two or more will cause misleading results.

In conducting multiple regression analysis,t-tests should be conducted prior to conducting the F-test.

In simple linear regression analysis,the regression model forms a straight line in two-dimensional space through the x,y data points,while a multiple regression model forms a plane through multidimensional space.

To describe variable credit status that has three levels: Excellent,Good,and Poor,we need to use two different dummy variables.

Exam 15: Multiple Regression Analysis and Model Building

Which of the following regression output values is used in computing the variance inflation factors?

Consider the following regression model: = B0 + B1x1 + B1 + ε.If B2 > 0,then the parabola will open downward and if B2 < 0,then the parabola will open downward.

A dummy variable is a dependent variable whose value is set at either zero or one.

The multiple coefficient of determination measures the percentage of variation in the dependent variable that is explained by the independent variables in the model.

In a multiple regression model where three independent variables are included in the model,the percentage of explained variation will be equal to the square of the sum of the correlations between the independent variables and the dependent variable.

The correlation matrix is an effective means of determining whether any of the independent variables has a curvilinear relationship with the dependent variable.

In the best subsets approach to regression analysis,if we start with 4 independent variables,a total of 33 different regression models will actually be computed for possible selection as the best model to use.

A multiple regression was conducted to predict the price of yachts in thousands of dollars.A dummy variable was included to indicate whether or not the yacht has a flying bridge,where 0 means "no" and 1 means "yes." Which of the following statements is correct using the 0.10 level of significance?

The multiple coefficient of determination is the average of all the squared correlations of the independent variables.

Which of the following statements is true?

Where there are two independent variables in a multiple regression,the regression equation forms a plane.

You should not include more than one categorical variable in a multiple regression because the use of two or more will cause misleading results.

In conducting multiple regression analysis,t-tests should be conducted prior to conducting the F-test.

In simple linear regression analysis,the regression model forms a straight line in two-dimensional space through the x,y data points,while a multiple regression model forms a plane through multidimensional space.

To describe variable credit status that has three levels: Excellent,Good,and Poor,we need to use two different dummy variables.

Consider the following regression model: = B₀ + B₁x₁ + B₁ + ε.If B₂ > 0,then the parabola will open downward and if B₂ < 0,then the parabola will open downward.