Question 1

For the following regression equation   ,a unit increase in x1,while holding x2 constant at a value of 2,decreases the value of y on average by:

Accepted Answer

A) 92 
B) 85 
C) 20 
D) an amount that depends on the value of x1. 
A) 92 
B) 85 
C) 20 
D) an amount that depends on the value of x1.

Question 2

Computer Training 
Consider the following data for two variables,x and y.The independent variable x represents the amount of training time (in hours)for a salesperson starting in a new computer store to adjust fully,and the dependent variable y represents the weekly sales (in $1000s).   Use statistical software to answer the following question(s). ​ ​
-{Computer Training Narrative} Determine if there is sufficient evidence at the 5% significance level to infer that the quadratic relationship between y,x,and x2 in the previous question is significant.

Accepted Answer

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

Question 3

Suppose that the sample regression line of the first-order model is   .If we examine the relationship between y and x1 for three different values of x2,we observe that the effect of x1 on y remains the same no matter what the value of x2.

Accepted Answer

A) True 
 B)False

Question 4

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} Do these results allow us to conclude at the 1% significance level that the model is useful in predicting the income of physicians?

Accepted Answer

H₀: β₁ = β₂ = β₃ = 0,H₁: At least one β_i is no

Question 5

In a stepwise regression procedure,if two independent variables are highly correlated,then:

Accepted Answer

A) neither variable will enter the equation. 
B) both variables will enter the equation 
C) only one variable will enter the equation. 
D) not enough information is given to answer this question. 
A) neither variable will enter the equation. 
B) both variables will enter the equation 
C) only one variable will enter the equation. 
D) not enough information is given to answer this question.

Question 6

Suppose that the sample regression equation of a second-order model is given by   .Then,the value 4.60 is the:

Accepted Answer

A) predicted value of y for any positive value of x. 
B) predicted value of y when x = 2. 
C) estimated change in y when x increases by 1 unit . 
D) intercept where the response surface strikes the x-axis. 
A) predicted value of y for any positive value of x. 
B) predicted value of y when x = 2. 
C) estimated change in y when x increases by 1 unit . 
D) intercept where the response surface strikes the x-axis.

Question 7

In a first-order model with two predictors x1 and x2,an interaction term may be used when the relationship between the dependent variable y and the predictor variables is linear.

Accepted Answer

A) True 
 B)False

Question 8

In general,to represent a nominal independent variable that has c possible categories,we would create (c− 1)dummy variables.

Accepted Answer

A) True 
 B)False

Question 9

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} Test to determine at the 10% significance level if the x2 term should be retained.

Accepted Answer

H₀: β₂ = 0 vs.H₁: β₂≠ 0 Rejection

Question 10

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} What is the multiple coefficient of determination? What does this statistic tell you about the model?

Accepted Answer

R² = .472.It means that 47.2% o

Question 11

The stepwise regression procedure begins by computing the multiple regression model for all independent variables of interest.

Accepted Answer

A) True 
 B)False

Question 12

If the odds ratio that an obese person who smokes 15 or more cigarettes per day suffers a heart attack is 9,then the probability that the person will suffer a heart attack is 0.81.

Accepted Answer

A) True 
 B)False

Question 13

In explaining starting salaries for graduates of psychology programs,which of the following independent variables would not best be represented with dummy variables?

Accepted Answer

A) Marital status 
B) Grade point average 
C) Race 
D) Gender 
A) Marital status 
B) Grade point average 
C) Race 
D) Gender

Question 14

Computer Training 
Consider the following data for two variables,x and y.The independent variable x represents the amount of training time (in hours)for a salesperson starting in a new computer store to adjust fully,and the dependent variable y represents the weekly sales (in $1000s).   Use statistical software to answer the following question(s). ​ ​
-{Computer Training Narrative} Determine the coefficient of determination quadratic model.What does this statistic tell you about this model?

Accepted Answer

Since R² = .819,this means that

Question 15

If a quadratic relationship exists between y and each of x1 and x2,you use a(n)____________________-order polynomial model.

Accepted Answer

Question 16

In general,to represent a nominal variable with m categories,we must create _______________ indicator variables.The last category represented by I1 = I2 = .....Im−1 = 0 is called the _______________ category.

Accepted Answer

m− 1; omit

Question 17

In stepwise regression,if two independent variables are highly correlated,both variables must enter the model simultaneously.

Accepted Answer

A) True 
 B)False

Question 18

The ____________________ variable of a regression model is the variable that you wish to analyze or predict.

Accepted Answer

The answer of The ____________________ variable of a regression model...

Question 19

In a multiple regression analysis,which procedure permits variables to enter and leave the model at different stages of its development?

Accepted Answer

A) Stepwise regression 
B) Backward elimination 
C) Residual analysis 
D) Forward selection 
A) Stepwise regression 
B) Backward elimination 
C) Residual analysis 
D) Forward selection

Question 20

Another name for an indicator variable is an interval variable.

Accepted Answer

A) True 
 B)False

For the following regression equation ,a unit increase in x₁,while holding x₂ constant at a value of 2,decreases the value of y on average by:

Suppose that the sample regression line of the first-order model is .If we examine the relationship between y and x₁ for three different values of x₂,we observe that the effect of x₁ on y remains the same no matter what the value of x₂.

In a stepwise regression procedure,if two independent variables are highly correlated,then:

Suppose that the sample regression equation of a second-order model is given by .Then,the value 4.60 is the:

In a first-order model with two predictors x₁ and x₂,an interaction term may be used when the relationship between the dependent variable y and the predictor variables is linear.

In general,to represent a nominal independent variable that has c possible categories,we would create (c− 1)dummy variables.

The stepwise regression procedure begins by computing the multiple regression model for all independent variables of interest.

If the odds ratio that an obese person who smokes 15 or more cigarettes per day suffers a heart attack is 9,then the probability that the person will suffer a heart attack is 0.81.

In explaining starting salaries for graduates of psychology programs,which of the following independent variables would not best be represented with dummy variables?

If a quadratic relationship exists between y and each of x₁ and x₂,you use a(n)____________________-order polynomial model.

In general,to represent a nominal variable with m categories,we must create _ indicator variables.The last category represented by I₁ = I₂ = .....Im−₁ = 0 is called the _ category.

In stepwise regression,if two independent variables are highly correlated,both variables must enter the model simultaneously.

The ____________________ variable of a regression model is the variable that you wish to analyze or predict.

In a multiple regression analysis,which procedure permits variables to enter and leave the model at different stages of its development?

Another name for an indicator variable is an interval variable.

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 x1,while holding x2 constant at a value of 2,decreases the value of y on average by:

Suppose that the sample regression line of the first-order model is .If we examine the relationship between y and x1 for three different values of x2,we observe that the effect of x1 on y remains the same no matter what the value of x2.

In a stepwise regression procedure,if two independent variables are highly correlated,then:

Suppose that the sample regression equation of a second-order model is given by .Then,the value 4.60 is the:

In a first-order model with two predictors x1 and x2,an interaction term may be used when the relationship between the dependent variable y and the predictor variables is linear.

In general,to represent a nominal independent variable that has c possible categories,we would create (c− 1)dummy variables.

The stepwise regression procedure begins by computing the multiple regression model for all independent variables of interest.

If the odds ratio that an obese person who smokes 15 or more cigarettes per day suffers a heart attack is 9,then the probability that the person will suffer a heart attack is 0.81.

In explaining starting salaries for graduates of psychology programs,which of the following independent variables would not best be represented with dummy variables?

If a quadratic relationship exists between y and each of x1 and x2,you use a(n)____________________-order polynomial model.

In general,to represent a nominal variable with m categories,we must create _______________ indicator variables.The last category represented by I1 = I2 = .....Im−1 = 0 is called the _______________ category.

In stepwise regression,if two independent variables are highly correlated,both variables must enter the model simultaneously.

The ____________________ variable of a regression model is the variable that you wish to analyze or predict.

In a multiple regression analysis,which procedure permits variables to enter and leave the model at different stages of its development?

Another name for an indicator variable is an interval variable.

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 x₁,while holding x₂ constant at a value of 2,decreases the value of y on average by:

Suppose that the sample regression line of the first-order model is .If we examine the relationship between y and x₁ for three different values of x₂,we observe that the effect of x₁ on y remains the same no matter what the value of x₂.

In a first-order model with two predictors x₁ and x₂,an interaction term may be used when the relationship between the dependent variable y and the predictor variables is linear.

If a quadratic relationship exists between y and each of x₁ and x₂,you use a(n)____________________-order polynomial model.

In general,to represent a nominal variable with m categories,we must create _ indicator variables.The last category represented by I₁ = I₂ = .....Im−₁ = 0 is called the _ category.