1. Slide 6 - 1 Copyright © 2009 Pearson Education, Inc. Active Learning Lecture Slides For use with Classroom Response Systems Intro Stats Third Edition by De Veaux, Velleman, Bock Chapter 6: The Standard Deviation as a Ruler and the Normal Model

2. Slide 6 - 2 Copyright © 2009 Pearson Education, Inc. Which of the following data summaries are changed by adding a constant to each data value? I. the mean II. the median III. the standard deviation A. I only B. III only C. I and II D. I and III E. I, II, and III

3. Slide 6 - 3 Copyright © 2009 Pearson Education, Inc. Which of the following data summaries are changed by adding a constant to each data value? I. the mean II. the median III. the standard deviation A. I only B. III only C. I and II D. I and III E. I, II, and III

4. Slide 6 - 4 Copyright © 2009 Pearson Education, Inc. The best estimate of the standard deviation of the men’s weights displayed in this dotplot is A. 10 pounds B. 15 pounds C. 25 pounds D. 40 pounds

5. Slide 6 - 5 Copyright © 2009 Pearson Education, Inc. The best estimate of the standard deviation of the men’s weights displayed in this dotplot is A. 10 pounds B. 15 pounds C. 25 pounds D. 40 pounds

6. Slide 6 - 6 Copyright © 2009 Pearson Education, Inc. Suppose that a Normal model describes fuel economy (miles per gallon) for automobiles and that a Saturn has a standardized (z-score) of +2.2. This means that Saturns... A.get 2.2 miles per gallon. B.get 2.2 miles per gallon more than the average car. C.have a standard deviation of 2.2. D.achieve fuel economy that is 2.2 standard deviations better than the average car.

7. Slide 6 - 7 Copyright © 2009 Pearson Education, Inc. Suppose that a Normal model describes fuel economy (miles per gallon) for automobiles and that a Saturn has a standardized (z-score) of +2.2. This means that Saturns... A.get 2.2 miles per gallon. B.get 2.2 miles per gallon more than the average car. C.have a standard deviation of 2.2. D.achieve fuel economy that is 2.2 standard deviations better than the average car.

8. Slide 6 - 8 Copyright © 2009 Pearson Education, Inc. Environmental researchers have collected data on rain acidity for years. Suppose that a Normal model describes the acidity (pH) of rainwater, and that water tested after last week’s storm had a z-score of 1.8. This means that the acidity of that rain... A.had a pH of 1.8. B.had a pH 1.8 times that of average rainwater. C.had a pH 1.8 standard deviations higher than that of average rainwater. D.had a pH 1.8 higher than average rainfall.

9. Slide 6 - 9 Copyright © 2009 Pearson Education, Inc. Environmental researchers have collected data on rain acidity for years. Suppose that a Normal model describes the acidity (pH) of rainwater, and that water tested after last week’s storm had a z-score of 1.8. This means that the acidity of that rain... A.had a pH of 1.8. B.had a pH 1.8 times that of average rainwater. C.had a pH 1.8 standard deviations higher than that of average rainwater. D.had a pH 1.8 higher than average rainfall.

10. Slide 6 - 10 Copyright © 2009 Pearson Education, Inc. Suppose a Normal model describes the number of pages printer ink cartridges last for. If we keep track of printed page counts for the 47 printers in the company’s office, which must be true? I. The page counts of those ink cartridges will be normally distributed. II. The histogram for those page counts will be symmetric. III. 95% of those page counts will be within 2 standard deviations of the mean. A. None B. I only C. II only D. II and III E. I, II, and III

11. Slide 6 - 11 Copyright © 2009 Pearson Education, Inc. Suppose a Normal model describes the number of pages printer ink cartridges last for. If we keep track of printed page counts for the 47 printers in the company’s office, which must be true? I. The page counts of those ink cartridges will be normally distributed. II. The histogram for those page counts will be symmetric. III. 95% of those page counts will be within 2 standard deviations of the mean. A. None B. I only C. II only D. II and III E. I, II, and III

12. Slide 6 - 12 Copyright © 2009 Pearson Education, Inc. Students taking an intro stats class reported the number of credit hours that they were taking that quarter. Summary statistics are shown in the table. Suppose the college charges $73 per credit hour plus a flat fee of $35 per quarter. For example, a student taking 12 credit hours would pay $35 + 12($73) = $911 for that quarter. What is the mean fee paid? A. $216.05 B. $1250.45 C. $251.05 D. $1205

13. Slide 6 - 13 Copyright © 2009 Pearson Education, Inc. Students taking an intro stats class reported the number of credit hours that they were taking that quarter. Summary statistics are shown in the table. Suppose the college charges $73 per credit hour plus a flat fee of $35 per quarter. For example, a student taking 12 credit hours would pay $35 + 12($73) = $911 for that quarter. What is the mean fee paid? A. $216.05 B. $1250.45 C. $251.05 D. $1205

14. Slide 6 - 14 Copyright © 2009 Pearson Education, Inc. Students taking an intro stats class reported the number of credit hours that they were taking that quarter. Summary statistics are shown in the table. Suppose the college charges $73 per credit hour plus a flat fee of $35 per quarter. For example, a student taking 12 credit hours would pay $35 + 12($73) = $911 for that quarter. What is the standard deviation for the fees paid? A. $216.08 B. $1250.48 C. $251.08 D. $1203

15. Slide 6 - 15 Copyright © 2009 Pearson Education, Inc. Students taking an intro stats class reported the number of credit hours that they were taking that quarter. Summary statistics are shown in the table. Suppose the college charges $73 per credit hour plus a flat fee of $35 per quarter. For example, a student taking 12 credit hours would pay $35 + 12($73) = $911 for that quarter. What is the standard deviation for the fees paid? A. $216.08 B. $1250.48 C. $251.08 D. $1203

16. Slide 6 - 16 Copyright © 2009 Pearson Education, Inc. Students taking an intro stats class reported the number of credit hours that they were taking that quarter. Summary statistics are shown in the table. Suppose the college charges $73 per credit hour plus a flat fee of $35 per quarter. For example, a student taking 12 credit hours would pay $35 + 12($73) = $911 for that quarter. What is the median fee paid? A. $216.08 B. $1250.48 C. $251.08 D. $1203

17. Slide 6 - 17 Copyright © 2009 Pearson Education, Inc. Students taking an intro stats class reported the number of credit hours that they were taking that quarter. Summary statistics are shown in the table. Suppose the college charges $73 per credit hour plus a flat fee of $35 per quarter. For example, a student taking 12 credit hours would pay $35 + 12($73) = $911 for that quarter. What is the median fee paid? A. $216.08 B. $1250.48 C. $251.08 D. $1203

18. Slide 6 - 18 Copyright © 2009 Pearson Education, Inc. In a Normal model, about 68% of the data fall within 2 standard deviations of the mean. A. True B. False

19. Slide 6 - 19 Copyright © 2009 Pearson Education, Inc. In a Normal model, about 68% of the data fall within 2 standard deviations of the mean. A. True B. False