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Exam 14: Introduction to Linear Regression and Correlation Analysis

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Question 61

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A perfect correlation between two variables will always produce a correlation coefficient of +1.0

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Question 62

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Which of the following statements is true?

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

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Question 63

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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?

State University recently randomly sampled ten students and analyzed grade point average (GPA)and number of hours worked off-campus per week.The following data were observed: In this study the independent variable is the number of hours worked off campus per week.

Assuming that a regression has been conducted for a group of small companies where x = the number of employees at the company,y = annual revenue of the company (recorded in thousands of dollars) ,and the largest company included in the study had 82 employees.The resulting regression equation is = 59.2 + 83.4x.Which of the following is true?

When calculating prediction intervals for predicted values of y based on a given x,all 95 percent prediction intervals will be of equal width.

In a simple linear regression analysis,if the test statistic for testing the significance of the regression slope coefficient is 3.6,the F ratio from the analysis of variance table is known to be 12.96

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 F statistic?

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?

The prediction interval developed from a simple linear regression model will be at its narrowest point when the value of x used to predict y is equal to the mean value of x.

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

In developing a scatter plot,the decision maker has the option of connecting the points or not.

It is believed that number of people who attend a Mardi Gras parade each year depends on the temperature that day.A regression has been conducted on a sample of years where the temperature ranged from 28 to 64 degrees and the number of people attending ranged from 8400 to 14,600.The regression equation was found to be = 2378 + 191x.Which of the following is true?

In a simple regression model,the slope coefficient represents the average change in the independent variable for a one-unit change in the dependent variable.

If two variables are highly correlated,it not only means that they are linearly related,it also means that a change in one variable will cause a change in the other variable.

Which of the following statements is true with respect to a simple linear regression model?

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 true?

A regression model that is deemed to have a regression slope coefficient that could be equal to zero should not be used for prediction since there is no established linear relationship between the x and y variable.

You are given the following sample data for two variables: The regression model based on these sample data explains approximately 75 percent of the variation in the dependent variable.

Explain what is meant by the term least squares regression model.