Chapter 13 QUIZ

759

TRUE OR FALSE

Question 13.158

1. True or false: We may check all the regression assumptions using a scatterplot of the residuals versus the fitted values.

Question 13.159

2. True or false: When , no relationship exists between the predictor variable and the response variable.

Question 13.160

3. True or false: For a given value of , the prediction interval for a randomly chosen value of is always wider than the confidence interval for the mean value of .

FILL IN THE BLANK

Question 13.161

4. Two other terms for the fitted values of a regression are the (a) __________ and the (b) __________ values.

Question 13.162

5. The point estimate of the slope __________of the population regression equation in Section 13.1 is __________.

Question 13.163

6. A predictor variable used to recode a binomial categorical variable in regression, and taking values 0 or 1, is called a __________ variable.

SHORT ANSWER

Question 13.164

7. What are the four regression assumptions?

Question 13.165

8. What other form of inference is the confidence interval for equivalent to?

Question 13.166

9. Why is preferable to in multiple regression?

CALCULATIONS AND INTERPRETATIONS

Question 13.167

heightweight

10. Men's Heights and Weights. The university medical unit is collecting data on the heights and weights of the male students on campus. A random sample of 10 male students showed the following heights (in inches, ) and weights (in pounds, ). Test for a linear relationship between height and weight, using level of significance .

Student Height Weight
1 66 150
2 68 145
3 69 160
4 70 165
5 70 165
6 71 180
7 72 175
8 72 180
9 73 195
10 75 210

Question 13.168

11. For the data in Problem 10, answer the following:

  1. Will a 99% confidence interval for include zero? Why or why not?
  2. Verify your statement in (a) by constructing and interpreting a 99% confidence interval for .

Question 13.169

12. Using the data in Problem 10, do the following:

  1. Find the point estimate of the height of a man 70 inches tall.
  2. Calculate and interpret a 95% confidence interval for the mean height of all men 70 inches tall.
  3. Compute and interpret a 95% prediction interval for a randomly chosen man 70 inches tall.

For Exercise 13, refer to the data in Review Exercises 10–13 (page 758).

Question 13.170

13. Report and interpret your final model from Exercise 12, by doing the following:

  1. Provide the multiple regression equation for your final model.
  2. Interpret the multiple regression coefficients so that a nonstatistician could understand.
  3. Report and interpret the standard error of the estimate and the adjusted coefficient of determination .