Question 1

Assume that you have calculated a prediction of  = 110 where the specific value for x is equal to the average value of x.Also assume that n = 201 and that the standard error of the estimate is sε = 4.5.Find the approximate 95 percent prediction interval.

Accepted Answer

A) About 101 ----- 119 
B) About 109.4 ----- 110.6 
C) About 105.5 ----- 104.5 
D) About 98.4 ----- 121.6

Question 2

When the intercept in a regression equation is deemed not significantly different from 0,then in making predictions for y,0.0 should be used as the value of the intercept rather than the estimated intercept value.

Accepted Answer

A) True 
 B)False

Question 3

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

Accepted Answer

A) The percent of variation in the dependent variable that is explained by the regression model is equal to the square of the correlation coefficient between the x and y variables. 
B) If the correlation coefficient between the x and y variables is negative,the sign on the regression slope coefficient will also be negative. 
C) If the correlation between the dependent and the independent variable is determined to be significant,the regression model for y given x will also be significant. 
D) All of the above are true.

Question 4

A correlation of -0.9 indicates a weak linear relationship between the variables.

Accepted Answer

A) True 
 B)False

Question 5

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.

Accepted Answer

A) True 
 B)False

Question 6

Both a scatter plot and the correlation coefficient can distinguish between a curvilinear and a linear relationship.

Accepted Answer

A) True 
 B)False

Question 7

If the correlation coefficient for two variables is computed to be a -0.70,the scatter plot will show the data to be downward sloping from left to right.

Accepted Answer

A) True 
 B)False

Question 8

In simple linear regression,the t-test for the slope and the F-test are both conducting the same hypothesis test.

Accepted Answer

A) True 
 B)False

Question 9

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

Accepted Answer

A) True 
 B)False

Question 10

A high coefficient of determination (R2)implies that the regression model will be a good predictor for future values of the dependent variable given the value of the independent variable.

Accepted Answer

A) True 
 B)False

Question 11

You are given the following sample data for two variables:  Based upon these sample data,and testing at the 0.05 level of significance,the critical value for testing whether the population correlation coefficient is equal to zero is t = 2.2622.

Accepted Answer

A) True 
 B)False

Question 12

Given the following regression equation,the predicted value for y when x = 0.5 is about 4.57.  ANOVA

Accepted Answer

A) True 
 B)False

Question 13

Given a sample of size n = 15 and a sample correlation of r = 0.7,the value of the test statistic for conducting a hypothesis test of the correlation is t = 3.53.

Accepted Answer

A) True 
 B)False

Question 14

Explain what the correlation coefficient measures and some detail of the key issues associated with it.Be sure to also discuss the concept of spurious correlation.

Accepted Answer

The answer of Explain what the correlation coefficient measures and...

Question 15

Given a regression equation of  = 16 + 2.3x we would expect that an increase in x of 2.0 would lead to an average increase of y of 4.6.

Accepted Answer

A) True 
 B)False

Question 16

If the correlation between two variables is known to be statistically significant at the 0.05 level,then the regression slope coefficient will also be significant at the 0.05 level.

Accepted Answer

A) True 
 B)False

Question 17

If the R-square value for a simple linear regression model is .80,the correlation between the two variables is known to be .64.

Accepted Answer

A) True 
 B)False

Question 18

In conducting a hypothesis test for a correlation,the correct probability distribution to use is the F distribution.

Accepted Answer

A) True 
 B)False

Question 19

You are given the following sample data for two variables:  The sample correlation coefficient for these data is approximately r = 0.755.

Accepted Answer

A) True 
 B)False

Question 20

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

Accepted Answer

A) True 
 B)False

Exam 14: Introduction to Linear Regression and Correlation Analysis

Assume that you have calculated a prediction of = 110 where the specific value for x is equal to the average value of x.Also assume that n = 201 and that the standard error of the estimate is s_ε = 4.5.Find the approximate 95 percent prediction interval.

When the intercept in a regression equation is deemed not significantly different from 0,then in making predictions for y,0.0 should be used as the value of the intercept rather than the estimated intercept value.

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

A correlation of -0.9 indicates a weak linear relationship between the variables.

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.

Both a scatter plot and the correlation coefficient can distinguish between a curvilinear and a linear relationship.

If the correlation coefficient for two variables is computed to be a -0.70,the scatter plot will show the data to be downward sloping from left to right.

In simple linear regression,the t-test for the slope and the F-test are both conducting the same hypothesis test.

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

A high coefficient of determination (R²)implies that the regression model will be a good predictor for future values of the dependent variable given the value of the independent variable.

You are given the following sample data for two variables: Based upon these sample data,and testing at the 0.05 level of significance,the critical value for testing whether the population correlation coefficient is equal to zero is t = 2.2622.

Given the following regression equation,the predicted value for y when x = 0.5 is about 4.57. ANOVA

Given a sample of size n = 15 and a sample correlation of r = 0.7,the value of the test statistic for conducting a hypothesis test of the correlation is t = 3.53.

Explain what the correlation coefficient measures and some detail of the key issues associated with it.Be sure to also discuss the concept of spurious correlation.

Given a regression equation of = 16 + 2.3x we would expect that an increase in x of 2.0 would lead to an average increase of y of 4.6.

If the correlation between two variables is known to be statistically significant at the 0.05 level,then the regression slope coefficient will also be significant at the 0.05 level.

If the R-square value for a simple linear regression model is .80,the correlation between the two variables is known to be .64.

In conducting a hypothesis test for a correlation,the correct probability distribution to use is the F distribution.

You are given the following sample data for two variables: The sample correlation coefficient for these data is approximately r = 0.755.

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