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 does the coefficient of tell you about the model?

b 3 = −1.15.This can be interpre

For the following regression equation ,a unit increase in x2,while holding x1 constant at a value of 3,decreases the value of y on average by:

A) 22 B) 50 C) 56 D) An amount that depends on the value of x2 A) 22 B) 50 C) 56 D) An amount that depends on the value of x2

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} Is there enough evidence at the 10% significance level to conclude that surgeons earn less on average than psychiatrists?

H 0 : β 3 = 0 vs.H 1 : β 3 < 0 Rejection

Exam 18: Model Building

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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,x₁ = number of motorcycles registered in the county (in 10,000),and x₂ = 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 does the coefficient of tell you about the model?

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Question 141

For the following regression equation ,a unit increase in x₂,while holding x₁ constant at a value of 3,decreases the value of y on average by:

(Multiple Choice)

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Question 142

An indicator variable is a nominal variable that can assume _______________ possible values.

(Short Answer)

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Question 143

In the first-order model ,a unit increase in x₂,while holding x₁ constant,increases the value of y on average by 5 units.

(True/False)

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Question 144

We can incorporate any nominal variable into regression analysis by creating one or more dummy variables,also known as:

(Multiple Choice)

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Question 145

A second-order polynomial model is shaped like a(n)____________________.

(Short Answer)

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Question 146

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 = β₀ + β₁x₁ + β₂x₂ + β₃x₃ + ε,where y = annual income (in $1,000),x₁ = years of experience,x₂ = 1 if physician and 0 if not,and x₃ = 1 if surgeons and 0 if not.The computer output is shown below. THE REGRESSION EQUATION IS y = 71.65 + 2.07x₁ + 10.16x₂− 7.44x₃ S = 42.6 R−Sq = 30.9% ANALYSIS OF VARIANCE -{Incomes of Physicians Narrative} Is there enough evidence at the 10% significance level to conclude that surgeons earn less on average than psychiatrists?

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Question 147

The model y = β₀ + β₁x₁ + β₂x₂ + ε is used whenever the statistician believes that,on average,y is linearly related to:

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Question 148

Showing 141 - 148 of 148

For the following regression equation ,a unit increase in x₂,while holding x₁ constant at a value of 3,decreases the value of y on average by:

An indicator variable is a nominal variable that can assume _______________ possible values.

In the first-order model ,a unit increase in x₂,while holding x₁ constant,increases the value of y on average by 5 units.

We can incorporate any nominal variable into regression analysis by creating one or more dummy variables,also known as:

A second-order polynomial model is shaped like a(n)____________________.

The model y = β₀ + β₁x₁ + β₂x₂ + ε is used whenever the statistician believes that,on average,y is linearly related to:

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 a value of 3,decreases the value of y on average by:

An indicator variable is a nominal variable that can assume _______________ possible values.

In the first-order model ,a unit increase in x2,while holding x1 constant,increases the value of y on average by 5 units.

We can incorporate any nominal variable into regression analysis by creating one or more dummy variables,also known as:

A second-order polynomial model is shaped like a(n)____________________.

The model y = β0 + β1x1 + β2x2 + ε is used whenever the statistician believes that,on average,y is linearly related to:

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 a value of 3,decreases the value of y on average by:

In the first-order model ,a unit increase in x₂,while holding x₁ constant,increases the value of y on average by 5 units.

The model y = β₀ + β₁x₁ + β₂x₂ + ε is used whenever the statistician believes that,on average,y is linearly related to: