Question 1

Use the following regression results to answer the question below.  ANOVA   In conducting a hypothesis test of the slope using a 0.05 level of significance,which of the following is correct?

Accepted Answer

A) The slope differs significantly from 0 because p = 0.205 is greater then 0.05. 
B) The slope does not differ significantly from 0 because p = 0.205 is greater then 0.05. 
C) The slope differs significantly from 0 because p = 0.003 is less then 0.05. 
D) The slope does not differ significantly from 0 because p = 0.003 is less then 0.05.

Question 2

A manufacturing company is interested in predicting the number of defects that will be produced each hour on the assembly line.The managers believe that there is a relationship between the defect rate and the production rate per hour.The managers believe that they can use production rate to predict the number of defects.The following data were collected for 10 randomly selected hours.  Given these sample data,the simple linear regression model for predicting the number of defects is approximately  = 5.67 + 0.048x.

Accepted Answer

A) True 
 B)False

Question 3

Explain why it is important to construct scatter plots prior to conducting regression analysis.

Accepted Answer

The answer of Explain why it is important to construct...

Question 4

A nation job placement company is interested in developing a model that might be used to explain the variation in starting salaries for college graduates based on the college GPA.The following data were collected through a random sample of the clients with which this company has been associated.  Based on this sample information,determine the least squares regression model,determine what percent of the variation in starting salaries is explained by GPA,and test to determine whether the regression model is statistically significant at the 0.05 level of significance.Also,develop a scatter plot of the data and locate the regression line on the scatter plot.

Accepted Answer

The answer of A nation job placement company is interested...

Question 5

When regression analysis is used for descriptive purposes,two of the main items of interest are whether the sign on the regression slope coefficient is positive or negative and whether the regression slope coefficient is significantly different from zero.

Accepted Answer

A) True 
 B)False

Question 6

If you were going to develop a scatter plot for the purpose of determining whether one of the assumptions of the regression model is being satisfied,which of the following is true?

Accepted Answer

A) The plot should illustrate a bell-shaped distribution to show that the residuals are normally distributed. 
B) The horizontal axis should show the fitted values for the dependent variable. 
C) The plot should illustrate a cone shaped look. 
D) The points should fall in a straight line.

Question 7

State University recently randomly sampled seven students and analyzed grade point average (GPA)and number of hours worked off-campus per week.The following data were observed:  In testing the significance of the regression slope coefficient for the independent variable,HOURS,the calculated test statistic is approximately t = -1.47.

Accepted Answer

A) True 
 B)False

Question 8

When a pair of variables has a positive correlation,the slope in the regression equation will always be positive.

Accepted Answer

A) True 
 B)False

Question 9

Which of the following statements is true in simple linear regression?

Accepted Answer

A) The standard error of the estimate is equal to the standard error of the slope. 
B) The total degrees of freedom are (n-2). 
C) The coefficient of determination is equal to the correlation of x and y. 
D) The p-value of the F test will equal the p-value of the t-test of the slope.

Question 10

The following regression output was generated based on a sample of utility customers.The dependent variable was the dollar amount of the monthly bill and the independent variable was the size of the house in square feet.  Based on this regression output,which of the following statements is not true?

Accepted Answer

A) The number of square feet in the house explains only about 2 percent of the variation in the monthly power bill. 
B) At an alpha level equal to 0.05,there is no basis for rejecting the hypothesis that the slope coefficient is equal to zero. 
C) The average increase in the monthly power bill is about 66.4 for each additional square foot of space in the house. 
D) The correlation of the monthly power bill with the square footage of the house is 0.149.

Question 11

Given a sample correlation r = -0.5 and a sample size of n = 30,the test statistic for testing whether the two variables are significantly correlated is approximately t = -3.055.

Accepted Answer

A) True 
 B)False

Question 12

The following regression output is available.Notice that some of the values are missing.  Given this information,what is the standard error of the estimate for the regression model?

Accepted Answer

A) About 36.18 
B) Approximately 6.02 
C) About 1.98 
D) 3.91

Question 13

If a set of data contains no values of x that are equal to zero,then the regression coefficient,b0,has no particular meaning.

Accepted Answer

A) True 
 B)False

Question 14

A study was recently done in which the following regression output was generated using Excel.
SUMMARY OUTPUT  ANOVA   Given this output,we would reject the null hypothesis that the population regression slope coefficient is equal to zero at the alpha = 0.05 level.

Accepted Answer

A) True 
 B)False

Question 15

Which of the following statements is true?

Accepted Answer

A) When using a simple linear regression analysis model for prediction purposes,the potential error in the forecast will be less when the value of x used to forecast y is closer to  . 
B) The accuracy of the regression forecast is improved if the standard error for the regression slope coefficient is reduced. 
C) The use of regression analysis as a means of predicting the value for a dependent variable is not impacted by sampling error since the regression model uses all sample data to arrive at the regression model. 
D) None of the above.

Question 16

Residual analysis is conducted to check whether regression assumptions are met.Which of the following is not an assumption made in simple linear regression?

Accepted Answer

A) Errors are independent of each other. 
B) Errors are normally distributed. 
C) Errors are linearly related to x. 
D) Errors have constant variance.

Question 17

The sign on the intercept coefficient in a simple regression model will always be the same as the sign on the correlation coefficient.

Accepted Answer

A) True 
 B)False

Question 18

The sum of the residuals in a least squares regression model will be zero only when the correlation between the x and y variables is statistically significant.

Accepted Answer

A) True 
 B)False

Question 19

A study was recently conducted by Major League Baseball to determine whether there is a correlation between attendance at games and the record of home team's opponent.In this study,the dependent variable would be the record of the home team's opponent.

Accepted Answer

A) True 
 B)False

Question 20

If two variables are uncorrelated,the sample correlation coefficient will be r = 0.00.

Accepted Answer

A) True 
 B)False

Exam 14: Introduction to Linear Regression and Correlation Analysis

Use the following regression results to answer the question below. ANOVA In conducting a hypothesis test of the slope using a 0.05 level of significance,which of the following is correct?

Explain why it is important to construct scatter plots prior to conducting regression analysis.

When regression analysis is used for descriptive purposes,two of the main items of interest are whether the sign on the regression slope coefficient is positive or negative and whether the regression slope coefficient is significantly different from zero.

If you were going to develop a scatter plot for the purpose of determining whether one of the assumptions of the regression model is being satisfied,which of the following is true?

When a pair of variables has a positive correlation,the slope in the regression equation will always be positive.

Which of the following statements is true in simple linear regression?

The following regression output was generated based on a sample of utility customers.The dependent variable was the dollar amount of the monthly bill and the independent variable was the size of the house in square feet. Based on this regression output,which of the following statements is not true?

Given a sample correlation r = -0.5 and a sample size of n = 30,the test statistic for testing whether the two variables are significantly correlated is approximately t = -3.055.

The following regression output is available.Notice that some of the values are missing. Given this information,what is the standard error of the estimate for the regression model?

If a set of data contains no values of x that are equal to zero,then the regression coefficient,b₀,has no particular meaning.

A study was recently done in which the following regression output was generated using Excel. SUMMARY OUTPUT ANOVA Given this output,we would reject the null hypothesis that the population regression slope coefficient is equal to zero at the alpha = 0.05 level.

Which of the following statements is true?

Residual analysis is conducted to check whether regression assumptions are met.Which of the following is not an assumption made in simple linear regression?

The sign on the intercept coefficient in a simple regression model will always be the same as the sign on the correlation coefficient.

The sum of the residuals in a least squares regression model will be zero only when the correlation between the x and y variables is statistically significant.

A study was recently conducted by Major League Baseball to determine whether there is a correlation between attendance at games and the record of home team's opponent.In this study,the dependent variable would be the record of the home team's opponent.

If two variables are uncorrelated,the sample correlation coefficient will be r = 0.00.