B Answers to Selected Problems

# Chapter 2

## Sections 2.1 and 2.2

3. (a) All the students of the graduation class. (b) All the students in the professor's class.

(c) GPA. 5. (a) Ratio (b) ratio (c) ratio (d) nominal (e) ratio (f) ordinal (g) ratio (h) ratio (i) interval (j) ratio (k) ratio (l) ratio (m) ordinal (n) nominal.

## Section 2.3

1. (b) (1, 2, 3, 4, 5) ~ (24%, 24%, 16%, 22%, 14%) (c) 48%. 3. (b) (1, 2, 3, 4, 5) ~ (30.56%, 22.22%, 13.89%, 8.33%, 25%) (c) 44.45%.

## Section 2.4

3. The line graph does not show any particular pattern. 5. The stem-and-leaf diagram with increment 5 is more informative. 9. (b) 13 days 11. Ninety percent of the parts have life spans between 20 and 48 months. Only one out of 30 parts has a life span more than 50 months. Two out of 30 parts have life spans less than 20 months. 15. (b) Median consumption of electricity in kilowatt-hours is 250 kilowatt-hours, maximum consumption is 310 kilowatt-hours, and minimum consumption is 206 kilowatt-hours.

## Section 2.5

1. (a) , med = 120.10, mode = 120.1 (b) 1.84 (c) approximately symmetric. 3. (a) , med = 23.00 (b) 4.73 (c) 100%. 5. (a) , med = 107.50, mode = 100 (b) range = 20, , S = 7.08, CV = 6.53 7. 3.75238. 9. (51,100 ...