Question 1

For the following regression equation   ,a unit increase in x2,while holding x1 constant at 1,changes the value of y on average by:

Accepted Answer

A) −5 
B) +5 
C) 10 
D) −10 
A) −5 
B) +5 
C) 10 
D) −10 D

Question 2

Motorcycle Fatalities
 A traffic consultant has analyzed the factors that affect the number of motorcycle fatalities.She has come to the conclusion that two important variables are the number of motorcycle and the number of cars.She proposed the model   (the second-order model with interaction),where y = number of annual fatalities per county,xS1U1B11S1U1B0 = number of motorcycles registered in the county (in 10,000),and xS1U1B12S1U1B0 = number of cars registered in the county (in 1000).The computer output (based on a random sample of 35 counties)is shown below: THE REGRESSION EQUATION IS     S = 15.2 R−Sq = 47.2% ANALYSIS OF VARIANCE   ​ ​
-{Motorcycle Fatalities Narrative} Is there enough evidence at the 5% significance level to conclude that the model is useful in predicting the number of fatalities?

Accepted Answer

H₀: β₁ = β₂ = β₃ = β₄ = β₅ = 0 H₀: At least one β_i is not equal to zero Rejection region: F > F_.05,5,29 = 2.55 Test statistic: F = 5.181 Conclusion: Reject the null hypothesis.Yes,the model is useful in predicting the number of fatalities.

Question 3

A dummy variable is used as an independent variable in a regression model when:

Accepted Answer

A) the variable involved is interval. 
B) the variable involved is nominal. 
C) a curvilinear relationship is suspected. 
D) two independent variables interact. 
A) the variable involved is interval. 
B) the variable involved is nominal. 
C) a curvilinear relationship is suspected. 
D) two independent variables interact. B

Question 4

Motorcycle Fatalities
 A traffic consultant has analyzed the factors that affect the number of motorcycle fatalities.She has come to the conclusion that two important variables are the number of motorcycle and the number of cars.She proposed the model   (the second-order model with interaction),where y = number of annual fatalities per county,xS1U1B11S1U1B0 = number of motorcycles registered in the county (in 10,000),and xS1U1B12S1U1B0 = number of cars registered in the county (in 1000).The computer output (based on a random sample of 35 counties)is shown below: THE REGRESSION EQUATION IS     S = 15.2 R−Sq = 47.2% ANALYSIS OF VARIANCE   ​ ​
-{Motorcycle Fatalities Narrative} Test at the 1% significance level to determine if the x1 term should be retained in the model.

Accepted Answer

H₀: β₁ = 0 vs.H₁: β₁≠ 0 Rejection region: |

Question 5

Incomes of Physicians
 An economist is analyzing the incomes of physicians (general practitioners,surgeons,and psychiatrists).He realizes that an important factor is the number of years of experience.However,he wants to know if there are differences among the three professional groups.He takes a random sample of 125 physicians and estimates the multiple regression model y = βS1U1B10S1U1B0 + βS1U1B11S1U1B0xS1U1B11S1U1B0 + βS1U1B12S1U1B0xS1U1B12S1U1B0 + βS1U1B13S1U1B0xS1U1B13S1U1B0 + ε,where y = annual income (in $1,000),xS1U1B11S1U1B0 = years of experience,xS1U1B12S1U1B0 = 1 if physician and 0 if not,and xS1U1B13S1U1B0 = 1 if surgeons and 0 if not.The computer output is shown below. THE REGRESSION EQUATION IS y = 71.65 + 2.07xS1U1B11S1U1B0 + 10.16xS1U1B12S1U1B0− 7.44xS1U1B13S1U1B0   S = 42.6 R−Sq = 30.9% ANALYSIS OF VARIANCE   ​ ​
-{Incomes of Physicians Narrative} Estimate the annual income for a psychiatrist with 15 years of experience.

Accepted Answer

$102.70 (i

Question 6

Because indicator variables represent different groups,t-tests on the indicator variables allow us to draw inferences about the ____________________ in y between the groups.

Accepted Answer

The answer of Because indicator variables represent different groups,t-tests on...

Question 7

A first-order polynomial model with one predictor variable is the familiar simple linear regression model.

Accepted Answer

A) True 
 B)False

Question 8

Suppose that the sample regression equation of a model is   .If we examine the relationship between y and x2 for x1 = 1,2,and 3,we observe that the three equations produced not only differ in the intercept term,but the coefficient of x2 also varies.

Accepted Answer

A) True 
 B)False

Question 9

In a first-order model with two predictors x1 and x2,an interaction term may be used when the:

Accepted Answer

A) relationship between the dependent variable and the independent variables is linear. 
B) effect of x1 on the dependent variable is influenced by x2. 
C) Effect of x2 on the dependent variable is influenced by x1. 
D)  both b and c. 
A) relationship between the dependent variable and the independent variables is linear. 
B) effect of x1 on the dependent variable is influenced by x2. 
C) Effect of x2 on the dependent variable is influenced by x1. 
D)  both b and c.

Question 10

In explaining the income earned by college graduates,which of the following independent variables is best represented by a dummy variable?

Accepted Answer

A) Grade point average 
B) Age 
C) Number of years since graduating from high school 
D) College major 
A) Grade point average 
B) Age 
C) Number of years since graduating from high school 
D) College major

Question 11

Hockey Teams
 An avid hockey fan was in the process of examining the factors that determine the success or failure of hockey teams.He noticed that teams with many rookies and teams with many veterans seem to do quite poorly.To further analyze his beliefs he took a random sample of 20 teams and proposed a second-order model with one independent variable,average years of professional experience.The selected model is y = βS1U1B10S1U1B0 + βS1U1B11S1U1B0x + βS1U1B12S1U1B0xS1U1P12S1S1P0 + ε,where y = winning team's percentage,and x = average years of professional experience.The computer output is shown below. THE REGRESSION EQUATION IS y = 32.6 + 5.96x− .48xS1U1P12S1S1P0   S = 16.1 R−Sq = 43.9% ANALYSIS OF VARIANCE   ​ ​
-{Hockey Teams Narrative} Do these results allow us to conclude at the 5% significance level that the model is useful in predicting the team's winning percentage?

Accepted Answer

H₀: β₁ = β₂ = 0 vs.H₁: At least one β_i is not

Question 12

It is not possible to incorporate nominal variables into a regression model.

Accepted Answer

A) True 
 B)False

Question 13

The model   is used whenever the statistician believes that,on average,y is linearly related to x1 and x2 and the predictor variables do not interact.

Accepted Answer

A) True 
 B)False

Question 14

Which of the following statements about dummy variablesis false?

Accepted Answer

A) We can incorporate any nominal variable into regression analysis by creating one or more dummy variables. 
B) Dummy variables are also known as binary variables,nominal variables,or indicator variables. 
C) These variables take on only two values,namely 0 or 1,and those values then indicate the absence or presence of a particular nominal characteristic. 
D) All of these choices are true. 
A) We can incorporate any nominal variable into regression analysis by creating one or more dummy variables. 
B) Dummy variables are also known as binary variables,nominal variables,or indicator variables. 
C) These variables take on only two values,namely 0 or 1,and those values then indicate the absence or presence of a particular nominal characteristic. 
D) All of these choices are true.

Question 15

Suppose that the sample regression line of the first-order model is   .If we examine the relationship between y and x1 for four different values of x2,we observe that the:

Accepted Answer

A) only difference in the four equations produced is the coefficient of x2. 
B) effect of x1 on y remains the same no matter what the value of x2. 
C) effect of x1 on y remains the same no matter what the value of x1. 
D) Cannot answer this question without more information. 
A) only difference in the four equations produced is the coefficient of x2. 
B) effect of x1 on y remains the same no matter what the value of x2. 
C) effect of x1 on y remains the same no matter what the value of x1. 
D) Cannot answer this question without more information.

Question 16

Another term for a first-order polynomial model is a regression ____________________.

Accepted Answer

The answer of Another term for a first-order polynomial model...

Question 17

To include a nominal variable in the regression model we need to transform it into:

Accepted Answer

A) the intercept 
B) an indicator variable 
C) an interaction term 
D) a polynomial term 
A) the intercept 
B) an indicator variable 
C) an interaction term 
D) a polynomial term

Question 18

____________________ regression is an iterative procedure that adds and deletes one independent variable at a time to/from the regression model.

Accepted Answer

The answer of ____________________ regression is an iterative procedure that...

Question 19

The model y = β0 + β1x + β2x2 +.........+ βpxp + ε is referred to as a polynomial model with:

Accepted Answer

A) one predictor variable. 
B) p predictor variables. 
C) (p + 1)predictor variables. 
D) x predictor variables. 
A) one predictor variable. 
B) p predictor variables. 
C) (p + 1)predictor variables. 
D) x predictor variables.

Question 20

The model y = β0 + β1x1 + β2x2 + ε is a(n)____________________-order polynomial model with ____________________ predictor variable(s).

Accepted Answer

first; two

For the following regression equation ,a unit increase in x₂,while holding x₁ constant at 1,changes the value of y on average by:

A dummy variable is used as an independent variable in a regression model when:

Because indicator variables represent different groups,t-tests on the indicator variables allow us to draw inferences about the ____________________ in y between the groups.

A first-order polynomial model with one predictor variable is the familiar simple linear regression model.

Suppose that the sample regression equation of a model is .If we examine the relationship between y and x₂ for x₁ = 1,2,and 3,we observe that the three equations produced not only differ in the intercept term,but the coefficient of x₂ also varies.

In a first-order model with two predictors x₁ and x₂,an interaction term may be used when the:

In explaining the income earned by college graduates,which of the following independent variables is best represented by a dummy variable?

It is not possible to incorporate nominal variables into a regression model.

The model is used whenever the statistician believes that,on average,y is linearly related to x₁ and x₂ and the predictor variables do not interact.

Which of the following statements about dummy variablesis false?

Suppose that the sample regression line of the first-order model is .If we examine the relationship between y and x₁ for four different values of x₂,we observe that the:

Another term for a first-order polynomial model is a regression ____________________.

To include a nominal variable in the regression model we need to transform it into:

____________________ regression is an iterative procedure that adds and deletes one independent variable at a time to/from the regression model.

The model y = β₀ + β₁x + β₂x² +.........+ β_px^p + ε is referred to as a polynomial model with:

The model y = β₀ + β₁x₁ + β₂x₂ + ε is a(n)-order polynomial model with predictor variable(s).

What Is Statistics

Graphical Descriptive Techniques 1

Graphical Descriptive Techniques 2

Numerical Descriptive Techniques

Data Collection and Sampling

Probability

Random Variables and Discrete Probability Distributions

Continuous Probability Distributions

Sampling Distributions

Introduction to Estimation

Introduction to Hypothesis Testing

Inference About a Population

Inference About Comparing Two Populations

Analysis of Variance

Chi-Squared Tests

Simple Linear Regression and Correlation

Multiple Regression

Nonparametric Statistics

Time-Series Analytics and Forecasting

Statistical Process Control

Decision Analysis

Conclusion

Filters

Exam 18: Model Building

For the following regression equation ,a unit increase in x2,while holding x1 constant at 1,changes the value of y on average by:

A dummy variable is used as an independent variable in a regression model when:

Because indicator variables represent different groups,t-tests on the indicator variables allow us to draw inferences about the ____________________ in y between the groups.

A first-order polynomial model with one predictor variable is the familiar simple linear regression model.

Suppose that the sample regression equation of a model is .If we examine the relationship between y and x2 for x1 = 1,2,and 3,we observe that the three equations produced not only differ in the intercept term,but the coefficient of x2 also varies.

In a first-order model with two predictors x1 and x2,an interaction term may be used when the:

In explaining the income earned by college graduates,which of the following independent variables is best represented by a dummy variable?

It is not possible to incorporate nominal variables into a regression model.

The model is used whenever the statistician believes that,on average,y is linearly related to x1 and x2 and the predictor variables do not interact.

Which of the following statements about dummy variablesis false?

Suppose that the sample regression line of the first-order model is .If we examine the relationship between y and x1 for four different values of x2,we observe that the:

Another term for a first-order polynomial model is a regression ____________________.

To include a nominal variable in the regression model we need to transform it into:

____________________ regression is an iterative procedure that adds and deletes one independent variable at a time to/from the regression model.

The model y = β0 + β1x + β2x2 +.........+ βpxp + ε is referred to as a polynomial model with:

The model y = β0 + β1x1 + β2x2 + ε is a(n)____________________-order polynomial model with ____________________ predictor variable(s).

What Is Statistics

Graphical Descriptive Techniques 1

Graphical Descriptive Techniques 2

Numerical Descriptive Techniques

Data Collection and Sampling

Probability

Random Variables and Discrete Probability Distributions

Continuous Probability Distributions

Sampling Distributions

Introduction to Estimation

Introduction to Hypothesis Testing

Inference About a Population

Inference About Comparing Two Populations

Analysis of Variance

Chi-Squared Tests

Simple Linear Regression and Correlation

Multiple Regression

Nonparametric Statistics

Time-Series Analytics and Forecasting

Statistical Process Control

Decision Analysis

Conclusion

Filters

For the following regression equation ,a unit increase in x₂,while holding x₁ constant at 1,changes the value of y on average by:

Suppose that the sample regression equation of a model is .If we examine the relationship between y and x₂ for x₁ = 1,2,and 3,we observe that the three equations produced not only differ in the intercept term,but the coefficient of x₂ also varies.

In a first-order model with two predictors x₁ and x₂,an interaction term may be used when the:

The model is used whenever the statistician believes that,on average,y is linearly related to x₁ and x₂ and the predictor variables do not interact.

Suppose that the sample regression line of the first-order model is .If we examine the relationship between y and x₁ for four different values of x₂,we observe that the:

The model y = β₀ + β₁x + β₂x² +.........+ β_px^p + ε is referred to as a polynomial model with:

The model y = β₀ + β₁x₁ + β₂x₂ + ε is a(n)-order polynomial model with predictor variable(s).