Question 1

In a university statistics course a correlation of -0.8 was found between numbers of classes missed and course grade.This means that the fewer classes students missed the higher the grade.

Accepted Answer

A) True 
 B)False

Question 2

Use the following regression results to answer the question below.  ANOVA   Which of the following is true?

Accepted Answer

A) The correlation between x and y must be approximately 0.8851. 
B) The correlation between x and y must be approximately -0.8851. 
C) The correlation between x and y must be approximately 0.7835. 
D) The correlation between x and y must be approximately -0.7835.

Question 3

A recent study of 15 shoppers showed that the correlation between the time spent in the store and the dollars spent was 0.235.Using a significance level equal to 0.05,which of the following is the test statistic for testing whether the true population correlation is equal to zero?

Accepted Answer

A) t = 0.245 
B) t = 1.76 
C) t = 2.1604 
D) t = 0.872

Question 4

A recent study by a major financial investment company was interested in determining whether the annual percentage change in stock price for companies is linearly related to the annual percent change in profits for the company.The following data was determined for 8 randomly selected companies:  Based upon this sample information,what portion of variation in stock price percentage change is explained by the percent change in yearly income?

Accepted Answer

A) Approximately 70 percent 
B) Nearly 19 percent 
C) About 49 percent 
D) None of the above

Question 5

A study was recently performed by the Internal Revenue Service to determine how much tip income waiters and waitresses should make based on the size of the bill at each table.A random sample of bills and resulting tips were collected and the following regression results were observed:
SUMMARY OUTPUT  ANOVA   Given this output,the upper limit for the 95 percent confidence interval estimate for the true regression slope coefficient is approximately 0.28.

Accepted Answer

A) True 
 B)False

Question 6

If a pair of variables have a strong curvilinear relationship,which of the following is true?

Accepted Answer

A) The correlation coefficient will be able to indicate that curvature is present. 
B) A scatter plot will not be needed to indicate that curvature is present. 
C) The correlation coefficient will not be able to indicate the relationship is curved. 
D) The correlation coefficient will be equal to zero.

Question 7

Consider the following partially completed computer printout for a regression analysis where the dependent variable is the price of a personal computer and the independent variable is the size of the hard drive.  Based on the information provided,what is the estimate for the standard error of the estimate for the regression model?

Accepted Answer

A) Approximately 690.50 
B) About 4,026 
C) Just under 376.23 
D) 476,800

Question 8

The following regression model has been computed based on a sample of twenty observations:  = 34.2 + 19.3x.Given this model,the predicted value for y when x = 40 is 806.2.

Accepted Answer

A) True 
 B)False

Question 9

Which of the following is NOT an assumption for the simple linear regression model?

Accepted Answer

A) The individual error terms are statistically independent. 
B) The distribution of the error terms will be skewed left or right depending on the shape of the dependent variable. 
C) The error terms have equal variances for all values of the independent variable. 
D) The mean of the dependent variable value for all levels of x can be connected by a straight line.

Question 10

A cellular phone service provider believes that there is negative correlation between the minutes used by its customers and the age of the customer.To test this,the following would be the appropriate null and alternative hypotheses:

Accepted Answer

A) True 
 B)False

Question 11

A study was recently done in which the following regression output was generated using Excel.
SUMMARY OUTPUT  ANOVA   Given this,we know that approximately 57 percent of the variation in y variable is explained by the x variable.

Accepted Answer

A) True 
 B)False

Question 12

A positive population slope of 12 (β1 = 12)means that a 1-unit increase in x causes an average 12-unit increase in y.

Accepted Answer

A) True 
 B)False

Question 13

Which of the following is a correct interpretation for the regression slope coefficient?

Accepted Answer

A) For a one-unit change in y,we can expect the value of the independent variable to change by b1 units on average. 
B) For each unit change in x,the dependent variable will change by b1 units. 
C) The average change in y of a one-unit change in x will be b1 units. 
D) The average change in x of a one-unit change in y will be b1 units.

Question 14

If the correlation of x and y is -0.65,then coefficient of determination is -0.4225.

Accepted Answer

A) True 
 B)False

Question 15

In a simple regression model,if the regression model is deemed to be statistically significant,it means that the regression slope coefficient is significantly greater than zero.

Accepted Answer

A) True 
 B)False

Question 16

The values of the regression coefficients are found such the sum of the residuals is minimized.

Accepted Answer

A) True 
 B)False

Question 17

A dependent variable is the variable that we wish to predict or explain in a regression model.

Accepted Answer

A) True 
 B)False

Question 18

In analyzing the relationship between two variables,a scatter plot can be used to detect which of the following?

Accepted Answer

A) A positive linear relationship 
B) A curvilinear relationship 
C) A negative linear relationship 
D) All of the above

Question 19

If a simple least squares regression model is developed based on sample where the two variables are known to be positively correlated,the sign on the regression coefficient will be positive also.

Accepted Answer

A) True 
 B)False

Question 20

The following regression output is available.Notice that some of the values are missing.  Given this information,what is the test statistic for testing whether the regression slope coefficient is equal to zero?

Accepted Answer

A) Approximately t = 3.04 
B) About t = 2.19 
C) About t = 9.24 
D) About t = 2.39

Exam 14: Introduction to Linear Regression and Correlation Analysis

In a university statistics course a correlation of -0.8 was found between numbers of classes missed and course grade.This means that the fewer classes students missed the higher the grade.

Use the following regression results to answer the question below. ANOVA Which of the following is true?

A recent study of 15 shoppers showed that the correlation between the time spent in the store and the dollars spent was 0.235.Using a significance level equal to 0.05,which of the following is the test statistic for testing whether the true population correlation is equal to zero?

If a pair of variables have a strong curvilinear relationship,which of the following is true?

The following regression model has been computed based on a sample of twenty observations: = 34.2 + 19.3x.Given this model,the predicted value for y when x = 40 is 806.2.

Which of the following is NOT an assumption for the simple linear regression model?

A cellular phone service provider believes that there is negative correlation between the minutes used by its customers and the age of the customer.To test this,the following would be the appropriate null and alternative hypotheses:

A study was recently done in which the following regression output was generated using Excel. SUMMARY OUTPUT ANOVA Given this,we know that approximately 57 percent of the variation in y variable is explained by the x variable.

A positive population slope of 12 (β₁ = 12)means that a 1-unit increase in x causes an average 12-unit increase in y.

Which of the following is a correct interpretation for the regression slope coefficient?

If the correlation of x and y is -0.65,then coefficient of determination is -0.4225.

In a simple regression model,if the regression model is deemed to be statistically significant,it means that the regression slope coefficient is significantly greater than zero.

The values of the regression coefficients are found such the sum of the residuals is minimized.

A dependent variable is the variable that we wish to predict or explain in a regression model.

In analyzing the relationship between two variables,a scatter plot can be used to detect which of the following?

If a simple least squares regression model is developed based on sample where the two variables are known to be positively correlated,the sign on the regression coefficient will be positive also.

The following regression output is available.Notice that some of the values are missing. Given this information,what is the test statistic for testing whether the regression slope coefficient is equal to zero?