Answers section a1-a12

JWCL303_ans_A1-A12.qxd 4/20/10 10:10 AM Page AN1

ANSWERS TO SELECTED ODD-NUMBERED
EXERCISES AND SELF-REVIEW TESTS
(N
ote: Due to differences in rounding, the answers obtained by readers may differ slightly
from the ones given in this Appendix.)

Chapter 1 2.47 218, 245, 256, 329, 367, 383, 397, 404, 427, 433, 471, 523,
537, 551, 563, 581, 592, 622, 636, 647, 655, 678, 689, 810,
1.7 a. population b. sample c. population 841
d. sample e. population 2.67 d. 27.5% 2.69 c. 25% 2.71 c. 56.7%
1.11 a. number of dog bites reported last year 2.73 d. Boundaries of the fourth class are $4200.5 and $5600.5;
b. six c. six (cities) width ϭ $1400.
1.15 a. quantitative b. quantitative c. qualitative 2.87 No. The older group may drive more miles per week than
d. quantitative e. quantitative the younger group.
1.17 a. discrete b. continuous d. discrete
e. continuous
1.21 a. cross-section data b. cross-section data
Self-Review Test
c. time-series data d. time-series data
1.23 a. ⌺ f ϭ 66 b. ⌺m2 ϭ 1438 c. ⌺mf ϭ 926 2. a. 5 b. 7 c. 17 d. 6.5 e. 13
d. ⌺m f ϭ 17,922
2 f. 90 g. .30
1.25 a. ⌺x ϭ 112 b. ⌺y ϭ 45 c. ⌺xy ϭ 222 4. c. 35% 5. c. 70.8%
d. ⌺y2 ϭ 285 e. (⌺y)2 ϭ 2025 8. 30, 33, 37, 42, 44, 46, 47, 49, 51, 53, 53, 56, 60, 67,
1.27 a. ⌺x ϭ 856 b. (⌺x)2 ϭ 732,736 67, 71, 79
c. ⌺x ϭ 157,574
2

1.29 a. ⌺x ϭ 159 b. (⌺x)2 ϭ 25,281
c. ⌺x ϭ 4609
2 Chapter 3
1.33 a. sample b. population for the year 3.5 mode 3.9 mean ϭ 3.00; median ϭ 3.50; no mode
c. sample d. population 3.11 mean ϭ $3779.44; median ϭ $3250
1.35 a. sampling without replacement b. sampling with 3.13 a. mean ϭ $272.98 billion; median ϭ $162 billion
replacement b. mode ϭ $34 billion and $216 billion
1.37 a. ⌺x ϭ 45 b. (⌺x)2 ϭ 2025 3.15 mean ϭ £48.515 million; median ϭ £37.6 million
c. ⌺x ϭ 429
2
3.17 mean ϭ $529.67 million;
1.39 a. ⌺m ϭ 59 b. ⌺f 2 ϭ 2662 c. ⌺mf ϭ 1508 median ϭ $449.5 million; no mode
d. ⌺m f ϭ 24,884
2
e. ⌺m2 ϭ 867 3.19 mean ϭ 2.92 power outages; median ϭ 2.5 power
outages; mode ϭ 2 power outages
3.21 mean ϭ 29.4; median ϭ 27.5; mode ϭ 25
Self-Review Test 3.23 a. mean ϭ 1803; median ϭ 1270 b. outlier ϭ 5490;
1. b 2. c 3. a. sampling without replacement when the outlier is dropped: mean ϭ 1467.8;
b. sampling with replacement median ϭ 1166; mean changes by a larger amount
4. a. qualitative b. quantitative (continuous) c. median
c. quantitative (discrete) d. qualitative 3.25 combined mean ϭ $148.89 3.27 total ϭ $1055
6. a. ⌺x ϭ 29 b. (⌺x)2 ϭ 841 c. ⌺x 2 ϭ 231 3.29 age of the sixth person ϭ 60 years
7. a. ⌺m ϭ 45 b. ⌺f ϭ 112 c. ⌺m2 ϭ 495 3.31 mean for data set I ϭ 24.60; mean for data set II ϭ 31.60
d. ⌺mf ϭ 975 e. ⌺m2f ϭ 9855 f. ⌺f 2 ϭ 2994 The mean of the second data set is equal to the mean of
the first data set plus 7.
3.33 10% trimmed mean ϭ 38.25 years 3.35 weighted mean
ϭ 77.5
Chapter 2 3.41 range ϭ 25; ␴2 ϭ 61.5; ␴ ϭ 7.84
2.3 c. 30% d. 70% 3.43 a. x ϭ 9 sum of the deviations from the mean is zero.
2.5 c. 52% 2.7 c. 50% 2.15 d. 62% b. range ϭ 12; s2 ϭ 14.2857; s ϭ 3.78
2.19 d. 20% 2.29 c. 12 3.45 range ϭ 13; s2 ϭ 13.8409; s ϭ 3.72
2.35 c. 40% e. approximately 50% 2.43 6 teams 3.47 range ϭ 30 pieces; s2 ϭ 99.3; s ϭ 9.96 pieces

AN1


AN2 Answers to Selected Odd-Numbered Exercises and Self-Review Tests

3.49 range ϭ 7 stings; s2 ϭ 4.5769; s ϭ 2.14 stings 3.143 a. For men: mean ϭ 174.91 lbs ϭ 76,189.05 grams ϭ
3.51 range ϭ 30; s2 ϭ 107.4286; s ϭ 10.36 12.49 stone, median ϭ 179 lbs ϭ 77,970.61 grams ϭ
3.53 range ϭ 38; s2 ϭ 151.7778; s ϭ 12.3198 12.79 stone, and st. dev. ϭ 19.12 lbs ϭ 8328.48 grams ϭ
3.55 sϭ0 1.37 stone. For women: mean ϭ 124.95 lbs ϭ 54,426.97
3.57 CV for salaries ϭ 10.94%; CV for years of experience ϭ grams ϭ 8.93 stone, median ϭ 123 lbs ϭ 53,577.57 grams
13.33%; The relative variation in salaries is lower. ϭ 8.79 stone, st. dev. ϭ 17.48 lbs ϭ 7614.11 grams ϭ
3.59 s ϭ 14.64 for both data sets 1.25 stone. b. see answer to a, as answers are
3.63 x ϭ 9.40; s2 ϭ 37.7114; s ϭ 6.14 identical. c. yes d & e. Smaller unit has
3.65 ␮ ϭ 14.2 hours; ␴2 ϭ 42.61; ␴ ϭ 6.53 hours more variability.
3.67 x ϭ 19.67; s2 ϭ 67.6979; s ϭ 8.23 3.145 108 to 111
3.69 x ϭ 36.80 minutes; s2 ϭ 597.7143; s ϭ 24.45 minutes
3.71 a. x ϭ $139.05 c. x ϭ $138.93 Self-Review Test
3.75 at least 75%; at least 84%; at least 89% 1. b 2. a and d 3. c 4. c 5. b
3.77 68%; 95%; 99.7% 6. b 7. a 8. a 9. b 10. a 11. b
3.79 a. at least 75% b. at least 84% 12. c 13. a 14. a
c. at least 89% 15. mean ϭ 10.9; median ϭ 8; mode ϭ 6; range ϭ 26;
3.81 a. i. at least 75% ii. at least 89% s2 ϭ 65.2111; s ϭ 8.08
b. $1515 to $3215 19. b. x ϭ 19.46; s2 ϭ 44.0400; s ϭ 6.64
3.83 a. 99.7% b. 68% c. 95% 20. a. i. at least 84% ii. at least 89%
3.85 a. i. 99.7% ii. 68% b. 66 to 78 mph b. 2.9 to 11.7 years
3.91 a. Q1 ϭ 69; Q2 ϭ 72.5; Q3 ϭ 76; IQR ϭ 7 21. a. i. 68% ii. 99.7% b. 2.9 to 11.7 years
b. P35 ϭ 70 c. 28.57% 22. a. Q1 ϭ 3; Q2 ϭ 8; Q3 ϭ 13; IQR ϭ 10
3.93 a. Q1 ϭ 369; Q2 ϭ 386.5; Q3 ϭ 417; IQR ϭ 48 b. P60 ϭ 10 c. 66.67%
b. P57 ϭ 390 c. 73.33% 23. Data are skewed slightly to the right.
3.95 a. Q1 ϭ 25; Q2 ϭ 28.5; Q3 ϭ 33; IQR ϭ 8 24. combined mean ϭ $1066.43
b. P65 ϭ 31 c. 33.33% 25. GPA of fifth student ϭ 3.17
3.97 a. Q1 ϭ 533; Q2 ϭ 626.5; Q3 ϭ 728; 26. 10% trimmed mean ϭ 376.625; trimmed mean is a better
IQR ϭ 195 b. P30 ϭ 552.5 c. 23% measure
3.99 no outlier 27. a. mean for data set I ϭ 19.75; mean for data set II ϭ 16.75.
3.109 a. mean ϭ $106.5 thousand; median ϭ $76 thousand The mean of the second data set is equal to the mean of the
b. outlier ϭ 382; when the outlier is dropped: mean ϭ first data set minus 3. b. s ϭ 11.32 for both data sets.
$75.9 thousand; median ϭ $74 thousand; mean changes
by a larger amount c. median
3.111 a. mean ϭ 1973.6 points; median ϭ 1917.5 points;
Chapter 4
mode none b. range ϭ 544 points; 4.3 S ϭ {AB, AC, BA, BC, CA, CB}
s2 ϭ 42084.93; s ϭ 205.15 points 4.5 four possible outcomes; S ϭ {NN, NI, IN, II}
3.113 x ϭ 5.08 inches; s2 ϭ 6.8506; s ϭ 2.62 inches 4.7 four possible outcomes; S ϭ {DD, DG, GD, GG}
3.115 a. i. at least 75% ii. at least 89% 4.9 S ϭ {HHH, HHT, HTH, HTT, THH, THT, TTH, TTT}
b. 160 to 240 minutes 4.11 a. {NI and IN}; a compound event
3.117 a. i. 68% ii. 95% b. 140 to 260 minutes b. {II, NI, and IN}; a compound event
3.119 a. Q1 ϭ 60; Q2 ϭ 76; Q3 ϭ 97; IQR ϭ 37 c. {NN, IN, and NI}; a compound event
b. P70 ϭ 84 c. 70% d. {IN}; a simple event
3.121 The data set is skewed slightly to the right; 135 is an outlier. 4.13 a. {DG, GD, and GG}; a compound event
3.123 The minimum score is 172. b. {DG and GD}; a compound event
3.125 a. new mean ϭ 76.4 inches; new median ϭ 78 inches; new c. {GD}; a simple event
range ϭ 13 inches b. new mean ϭ 75.2 inches d. {DD, DG, and GD}; a compound event
3.127 mean ϭ $54.46 per barrel 4.19 Ϫ.55, 1.56, 5͞3, Ϫ1͞5
3.129 a. trimmed mean ϭ 9.5 b. 14.3% 4.21 not equally likely events; use relative frequency approach
3.131 a. age 30 and under: rate for A ϭ 25; rate for 4.23 subjective probability
B ϭ 20 b. age 31 and over: rate for A ϭ 100; rate 4.25 a. .48 b. .52 4.27 .66 4.29 .16
for B ϭ 85.7 c. overall: rate for A ϭ 50; rate for 4.31 a. .25 b. .75 4.33 .6667; .3333
B ϭ 58.3 d. Country A has the lower overall average 4.35 .42; .58 4.37 a. .086 b. .506
because 66.67% of its population is under 30. 4.39 use relative frequency approach 4.45 1296
3.133 a. k ϭ 1.41 b. k ϭ 2.24 3.135 b. median 4.47 a. not mutually exclusive b. dependent
3.137 b. For men: mean ϭ 82, median ϭ 79, modes ϭ 75, 79, c. A ϭ 51, 3, 4, 6, 86; P1A2 ϭ .625
and 92, s ϭ 12.08, Q1 ϭ 73.5, Q3 ϭ 89.5, and IQR ϭ 16. B ϭ 51, 2, 3, 6, 76; P1B2 ϭ .625
For women: mean ϭ 97.53, median ϭ 98, modes ϭ 94 4.49 48 4.51 960 4.53 a. i. .6250 ii. .6000
and 100, s ϭ 8.44, Q1 ϭ 94, Q3 ϭ 101, and IQR ϭ 7 iii. .4375 iv. .6400 b. The events “male” and
3.139 a. mean ϭ 30 b. mean ϭ 50 “female” are mutually exclusive. Events “have shopped”
3.141 a. at least 55.56% b. 1 to 11 inches and “male” are not mutually exclusive. c. Events
c. 2.66 to 9.34 inches “female” and “have shopped” are dependent.


Answers to Selected Odd-Numbered Exercises and Self-Review Tests AN3

4.55 a. i. .3900 ii. .5450 iii. .3448 20. a. i. .358 ii. .405 iii. .235 iv. .5593
iv. .3846 b. The events “male” and “in favor” are b. Events “woman” and “yes” are dependent but not
not mutually exclusive events “in favor” and “against” are mutually exclusive.
mutually exclusive. c. Events “female” and “no
opinion” are dependent. Chapter 5
4.57 a. i. .1333 ii. .4428 iii. .4744
5.3 a. discrete random variable b. continuous random
iv. .1700 b. The events “Airline A” and “more than
variable c. continuous random variable
1 hour late” are not mutually exclusive events “less than
d. discrete random variable e. discrete random
30 minutes late” and “more than 1 hour late” are mutually
variable f. continuous random variable
exclusive. c. Events “Airline B” and “30 minutes to
5.5 discrete random variable
1 hour late” are dependent.
5.9 a. not a valid probability distribution b. a valid
4.59 Events “female” and “pediatrician” are dependent not
probability distribution c. not a valid probability
mutually exclusive.
distribution
4.61 Events “female” and “business major” are dependent but
5.11 a. .19 b. .24 c. .48 d. .52
not mutually exclusive.
e. .52 f. .17 g. .71
4.63 P(A) ϭ .6667; P1A2 ϭ .3333 4.65 .86
5.13 b. i. .51 ii. .235 iii. .285 iv. .305
4.71 a. .4779 b. .1085
5.15 a. x 1 2 3 4 5
4.73 a. .1520 b. .1824
P(x) .10 .25 .30 .20 .15
4.75 a. .2462 b. .1086
b. approximate c. i. .30 ii. .65
4.77 .6923 4.79 .725 iii. .75 iv. .65
4.81 a. i. .3844 ii. .1590 b. .0000 5.17 x 0 1 2
4.83 a. i. .400 ii. .175 P(x) .5271 .3978 .0751
4.85 a. i. .225 ii. .035 b. .0000 5.19 x 0 1 2
4.87 .3529 4.89 .2667 4.91 .1600 P(x) .3969 .4662 .1369
4.93 a. .0064 b. .8464 4.95 .5120 5.21 x 0 1 2
4.97 .5278 4.99 .40 P(x) .4789 .4422 .0789
4.105 a. .56 b. .76 4.107 a. .52 b. .67 5.23 a. ␮ ϭ 1.590; ␴ ϭ .960 b. ␮ ϭ 7.070;
4.109 a. .6358 b. .9075 ␴ ϭ 1.061
4.111 a. .800 b. .775 c. 1.0 5.25 ␮ ϭ .480 errors; ␴ ϭ .911 errors
4.113 a. .780 b. .550 c. .790 5.27 ␮ ϭ 2.94 camcorders; ␴ ϭ 1.441 camcorders
4.115 .910 4.117 .77 5.29 ␮ ϭ 1.00 head; ␴ ϭ .707 head
4.119 .80 4.121 .80 4.123 .9744 5.31 ␮ ϭ 2.5604 tires; ␴ ϭ 1.3223 tires
4.125 a. .3333 b. .1000 5.33 ␮ ϭ .100 lemon; ␴ ϭ .308 lemon
4.127 a. i. .3640 ii. .4880 iii. .4297 5.35 ␮ ϭ $3.9 million; ␴ ϭ $3.015 million
iv. .6541 v. .2920 vi. .7080 5.37 ␮ ϭ .500 person; ␴ ϭ .584 person
b. Events “female” and “prefers watching sports” are 5.39 3! ϭ 6; (9 Ϫ 3)! ϭ 720; 9! ϭ 362,880;
dependent not mutually exclusive. (14 Ϫ 12)! ϭ 2; 5C3 ϭ 10; 7C4 ϭ 35; 9C3 ϭ 84;
4.129 a. i. .700 ii. .6296 iii. .275 iv. .725 4C0 ϭ 1; 3C3 ϭ 1; 6P2 ϭ 30; 8P4 ϭ 1680
b. Events “athlete” and “should be paid” are dependent 5.41 8C3 ϭ 56; 8P3 ϭ 336 5.43 12C3 ϭ 220; 12P3 ϭ 1320
not mutually exclusive. 5.45 25C4 ϭ 12,650; 25P4 ϭ 303,600
4.131 a. .7242 b. .2758 4.133 .0605 5.47 167,960
4.135 .0048 4.137 a. 17,576,000 b. 5200 5.51 a. not a binomial experiment
4.139 a. 1͞195,249,054 ϭ .0000000051 b. a binomial experiment
b. 1͞5,138,133 ϭ .00000019 c. a binomial experiment
4.141 a. .5000 b. .3333 c. sixth toss is independent 5.53 a. .2541 b. .1536 c. .3241
of the previous outcomes. Equivalent to part a. 5.55 b. ␮ ϭ 2.100; ␴ ϭ 1.212
4.143 a. .030 b. .150
5.59 a. 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 b. .1161
4.145 a. .50 b. .50 4.147 a. .8333 b. .1667
5.61 a. .0314 b. .3552 c. .8076
4.149 a. .01% b. i. .0048 ii. .0028
5.63 a. .0913 b. .0000 c. .0122
iii. .0222 iv. .0111 4.151 a. .8851
5.65 a. .3771 b. .1762
b. .0035
5.67 a. ␮ ϭ 5.6 customers; ␴ ϭ 1.058 customers b. .1147
5.69 a. ␮ ϭ 5.600 customers; ␴ ϭ 1.296 customers
Self-Review Test b. .0467
1. a 2. b 3. c 4. a 5. a 6. b 5.71 a. .4286 b. .0714 c. .5
7. c 8. b 9. b 10. c 11. b 5.73 a. .4286 b. .0048 c. .4524
12. 120 13. a. .3333 b. .6667 5.75 a. .4747; b. .0440 c. .3407
14. a. Events “female” and “out of state” are dependent but not 5.77 a. .2337 b. .2990 c. .9559
mutually exclusive. b. i. .4500 ii. .6364 5.81 a. .0404 b. .2565
15. .825 16. .3894 17. .4225 18. .40; .60 5.83 a. ␮ ϭ 1.3; ␴2 ϭ 1.3; ␴ ϭ 1.140 b. ␮ ϭ 2.1;
19. a. .279 b. .829 ␴2 ϭ 2.1; ␴ ϭ 1.449



5.85 .1607 5.87 .1185 6.41 a. 89.44% b. .62%
5.89 a. .1162 b. i. .6625 ii. .1699 6.43 a. .0197 b. .3296
iii. .4941 6.45 a. .8264 b. 12.83%
5.91 a. .3033 b. i. .0900 ii. .0018 6.47 a. 15.62% b. 7.64%
iii. .9098 6.49 a. 0.39% b. 1.46% c. 18.72%
5.93 a. .0031 b. i. .0039 ii. .4911 d. 29.21%
5.95 a. .2466 c. ␮ ϭ 1.4 ␴2 ϭ 1.4 6.51 0%
␴ ϭ 1.183 6.53 a. 2.00 b. Ϫ2.02 approximately
5.97 a. .0511 b. i. .0001 ii. .0070 c. Ϫ.37 approximately d. 1.02 approximately
iii. .0460 6.55 a. approximately 1.65 b. Ϫ1.96 c. Ϫ2.33
5.99 ␮ ϭ 4.11; ␴ ϭ 1.019; This mechanic repairs, on average, approximately d. 2.58 approximately
4.11 cars per day 6.57 a. 208.50 b. 241.25 c. 178.50
5.101 b. ␮ ϭ $557,000; ␴ ϭ $1,288,274; ␮ gives the d. 145.75 e. 158.25 f. 251.25
company’s expected profit. 6.59 19 minutes approximately
5.103 a. .0000 b. .0351 c. .7214 6.61 2060 kilowatt-hours
5.105 a. .9246 b. .0754 6.63 approximately $94.
6.65 np Ͼ 5 and nq Ͼ 5
5.107 a. .3692 b. .1429 c. .0923
6.67 a. .7688 b. .7697; difference is .0009
5.109 a. .8643 b. .1357
6.69 a. ␮ ϭ 84; ␴ ϭ 5.0199601 b. .0110
5.111 a. .0912 b. i. .5502 ii. .0817
c. .9817
iii. .2933
6.71 a. .0764 b. .6793 c. .8413 d. .8238
5.113 a. .2466
6.73 .0735 6.75 a. .0351 b. .1875 c. .1230
5.115 ⌺x P(x) ϭ Ϫ2.22. This game is not fair to you and you 6.77 a. .0332 b. 0 c. .9664
should not play as you expect to lose $2.22. 6.79 a. .7549 b. .2451
5.117 a. .0625 b. .125 c. .3125 6.81 a. .1093 b. 9.31% c. 57.33%
5.119 c. .7149 d. 3 nights d. It is possible, but its probability is close to zero.
5.121 8 cheesecakes 6.83 .0124 or 1.24%
5.123 a. 35 b. 10 c. .2857 5.127 $6 6.85 a. 848 hours b. 792 hours approximately
5.129 a. .0211 b. .0475 c. .4226 6.87 a. .0454 b. .0838 c. .8861 d. .2477
6.89 $2136 6.91 a. 85.08% b. $4000
Self-Review Test 6.93 .0091
2. probability distribution table 6.95 a. at most .0062 b. 65 mph
3. a 4. b 5. a 7. b 8. a 6.97 8.16 ounces
9. b 10. a 11. c 13. a 6.99 company A: $.0490 company B: $.0508
15. ␮ ϭ 2.040 homes; ␴ ϭ 1.449 homes 6.101 a. .7967 b. 62
16. a. i. .2128 ii. .8418 iii. .0153 6.105 .1064
b. ␮ ϭ 7.2 adults; ␴ ϭ 1.697 adults
17. a. .4525 b. .0646 c. .0666
18. a. i. .0521 ii. .2203 iii. .2013 Self-Review Test
1. a 2. a 3. d 4. b 5. a 6. c
7. b 8. b
Chapter 6 9. a. .1878 b. .9304 c. .0985 d. .7704
6.11 .8664 6.13 .9876 10. a. Ϫ1.28 approximately b. .61 c. 1.65
6.15 a. .4744 b. .4798 c. .1162 d. .0610 approximately d. Ϫ1.07 approximately
e. .9400 11. a. .5608 b. .0015 c. .0170 d. .1165
6.17 a. .0869 b. .0392 c. .9934 d. .9706 12. a. 48669.8 b. 40162
6.19 a. .5 approximately b. .5 approximately 13. a. i. .0318 ii. .9453 iii. .9099
c. 0 approximately d. 0 approximately iv. .0268 v. .4632 b. .7054 c. .3986
6.21 a. .9613 b. .4783 c. .4767 d. .0694
6.23 a. .0694 b. .2418 c. .0361 d. .9842
Chapter 7
6.25 a. .8365 b. .8947 c. approximately .5
d. approximately .5 e. approximately .00 7.5 a. 13.30 b. sampling error ϭ .14
f. approximately .00 c. sampling error ϭ .14; nonsampling error ϭ .12
6.27 a. 0.67 b. Ϫ2.67 c. Ϫ1.83 d. 1.50 d. x1 ϭ 11.44; x2 ϭ 13.89; x3 ϭ 14.00; x4 ϭ 13.56;
6.29 a. .4332 b. .1598 c. .3042 x5 ϭ 14.22; x6 ϭ 13.76; x7 ϭ 13.44;
6.31 a. .3336 b. .9564 c. .9686 x8 ϭ 13.33; x9 ϭ 12.78; x10 ϭ 12.56
d. approximately .00 7.7 b. x1 ϭ 40.25; x2 ϭ 39.25; x3 ϭ 38.50; x4 ϭ 32.25;
6.33 a. .2417 b. .7492 x5 ϭ 31.75; c. ␮ ϭ 36.40
6.35 a. .8212 b. .2810 c. .0401 d. .7190 7.13 a. mx ϭ 70; sx ϭ 2.357
6.37 a. .0764 b. .0062 b. mx ϭ 70; sx ϭ 1.118
6.39 a. .0985 b. .0538 7.15 a. sx ϭ 1.400 b. sx ϭ 2.500



7.17 a. n ϭ 100 b. n ϭ 256 b. mx ϭ 145 pounds; sx ϭ 1.800 pounds; approximately
7.19 mx ϭ $3.084; sx ϭ $.038 normal distribution
7.21 mx ϭ $520; sx ϭ $14.40 7.23 n ϭ 256 15. a. mx ϭ 45,000 miles; sx ϭ 527.71 miles; unknown
7.25 a. mx ϭ 80.60 b. sx ϭ 3.302 distribution
d. sx ϭ 3.302
b. mx ϭ 45,000 miles; sx ϭ 292.72 miles; approximately
7.33 mx ϭ 20.20 hours; sx ϭ .613 hours; the normal
normal distribution
distribution
16. a. .1541 b. .4582 c. .0003 d. .1706
7.35 mx ϭ 3.13; sx ϭ .075; sampling distribution is
e. .0084
approximately normal
17. a. i. .1203 ii. .1335 iii. .7486
7.37 n ϭ 20: mx ϭ 91.4 grams; sx ϭ 20.851 grams; skewed to
b. .9736 c. .0013
the right
n ϭ 75: mx ϭ 91.4 grams; sx ϭ $10.768 grams; 18. a. mp ϭ .048; sp ϭ .0302; unknown distribution
^ ^

approximately normal distribution b. mp ϭ .048; sp ϭ .0096; approximately normal
^ ^

7.39 mx ϭ 200 pieces; sx ϭ 15.821 pieces; approximately distribution
normal distribution; no, sample size Ն 30 c. mp ϭ .048; sp ϭ .0030; approximately normal
^ ^

7.41 86.64% distribution
7.43 a. z ϭ .22 b. z ϭ Ϫ3.63 c. z ϭ Ϫ1.83 19. a. i. .0080 ii. .4466 iii. .7823
d. z ϭ 3.17 iv. .2815 b. .5820 c. .1936 d. .0606
7.45 a. .1940 b. .8749
7.47 a. .0003 b. .9292
7.49 a. .2743 b. .1314 c. .5098 Chapter 8
7.51 a. .0150 b. .0968 c. .5696 8.11 a. 20.4 b. 19.07 to 21.73 c. 1.33
7.53 a. .8203 b. .9750 8.13 a. 70.59 to 79.01 b. 69.80 to 79.80
7.55 a. .1147 b. .9164 c. .1251 c. 68.22 to 81.38 d. yes
7.57 a. .1032 b. .3172 c. .0016 d. .9049 8.15 a. 77.84 to 85.96 b. 78.27 to 85.53
7.59 .0124 7.61 p ϭ .12; p ϭ .15
ˆ c. 78.65 to 85.15 d. yes
7.63 7125 subjects in the population; 312 subjects in the 8.17 a. 38 b. 37.07 to 38.93 c. .93
sample 8.19 a. n ϭ 254 b. n ϭ 51
7.65 sampling error ϭ Ϫ.04 8.21 a. n ϭ 299 b. n ϭ 126 c. n ϭ 61
7.71 a. mp ϭ .34; sp ϭ .027
^ ^
8.23 $283,762.77 to $290,937.23
b. mp ϭ .34; sp ϭ .016
^ ^ 8.25 a. 48,903.27 to 58,196.73 labor-hours
7.73 a. sp ϭ .051
^ b. sp ϭ .071
^ 8.27 31.83 to 31.93 ounces; does need an adjustment.
7.77 a. p ϭ .600 b. 5 d. Ϫ.10, .15, .15, Ϫ.10, 8.29 a. $1532.41 to $1617.59
Ϫ.10 8.31 n ϭ 167 8.33 n ϭ 61
7.79 mp ϭ .30; sp ϭ .034; approximately normal distribution
^ ^
8.41 a. t ϭ Ϫ1.333 b. t ϭ2.080 c. t ϭ3.333
7.81 mp ϭ .561; sp ϭ .027; approximately normal
^ ^
d. t ϭ Ϫ2.698
8.43 a. ␣ ഠ .10, left tail b. ␣ ϭ .005, right tail
distribution
c. ␣ ϭ .10, right tail d. ␣ ഠ .01 left tail
7.83 95.44%
8.45 a. t ϭ 2.080 b. t ϭ 1.671 c. t ϭ 2.807
7.85 a. z ϭ Ϫ.82 b. z ϭ 1.24 c. z ϭ Ϫ2.47
8.47 a. 1.78 b. Ϫ2.62 to 6.18 c. 4.40
d. z ϭ .62
8.49 a. 24.06 to 26.94 b. 23.58 to 27.42
7.87 a. .0721 b. .1798
c. 23.73 to 27.27
7.89 a. .0030 b. .2678
8.51 a. 91.03 to 93.87 b. 90.06 to 93.44
7.91 .0207 c. 88.06 to 91.20 d. confidence intervals of parts b
7.93 mx ϭ 750 hours; sx ϭ 11 hours; the normal distribution and c cover ␮, that of part a does not
7.95 a. .9131 b. .1698 c. .8262 d. .0344 8.53 40.04 to 42.36 bushels
7.97 a. .489 b. .0006 c. .8064 d. .8643 8.55 .39 to .43 gram
7.99 mp ϭ .88; sp ϭ .036; approximately normal distribution
^ ^ 8.57 18.64 to 25.36 minutes
7.101 a. i. .0146 ii. .0907 b. .9912 c. .0146 8.59 a. 21.56 to 24.44 hours
7.103 .6318 8.61 4.88 to 11.12 hours
7.105 10 approximately 8.63 7.29 to 8.27 ounces
7.107 a. .8023 b. 754 approximately 8.65 a. 6.18 years
7.109 .0035 b. 5.85 to 6.51 years; margin of error: Ϯ.33 year
8.71 a. yes, sample size is large b. no, sample size is
Self-Review Test not large c. yes, sample size is large d. yes,
sample size is large
1. b 2. b 3. a 4. a 5. b 8.73 a. .297 to .343 b. .336 to .384
6. b 7. c 8. a 9. a c. .277 to .323 d. confidence intervals of parts a and
10. a 11. c 12. a b cover p, but that of part c does not
14. a. mx ϭ 145 pounds; sx ϭ 3.600 pounds; approximately 8.75 a. .189 to .351 b. .202 to .338
normal distribution c. .218 to .322 d. yes

JWCL303_ans_A1-A12.qxd 4/20/10 1:44 PM Page AN6


8.77 a. .284 to .336 b. .269 to .351 9.29 a. reject H0 if z Ͼ 1.65 b. reject H0 if z Ͻ Ϫ1.65
c. .209 to .411 d. yes c. reject H0 if z Ͻ Ϫ1.96 or z Ͼ 1.96
8.79 a. n ϭ 668 b. n ϭ 671 9.31 a. critical value: z ϭ Ϫ1.96; test statistic: z ϭ Ϫ2.67;
8.81 a. n ϭ 1432 b. n ϭ 196 c. n ϭ 353 reject H0 b. critical value: z ϭ Ϫ1.96; test statistic:
8.83 a. .305 to .435 z ϭ Ϫ1.00; do not reject H0
8.85 a. 47% b. 38.9% to 55.1% 9.33 a. critical values: z ϭ Ϫ1.65 and 1.65; test statistic: z ϭ
8.87 a. 20.3% to 55.7% 8.89 a. 12.3% to 17.1% Ϫ1.34; do not reject H0 b. critical value: z ϭ Ϫ2.33;
8.91 a. .333 b. 8.5% to 58.1% test statistic: z ϭ Ϫ6.44; reject H0
8.93 n ϭ 173 c. critical value: z ϭ 1.65; test statistic: z ϭ 8.70;
8.95 n ϭ 1849 reject H0
8.99 a. $2640 9.35 a. H0: ␮ ϭ 45 months; H1: ␮ Ͻ 45 months;
b. $2514.57 to $2765.43 p value ϭ .0901; do not reject H0 b. z is Ϫ1.96;
8.101 3.969 to 4.011 inches; the machine needs to be adjusted do not reject
8.103 12.5 to 16.5 gallons 9.37 a. H0 : ␮ Ն 25 years; H1 Ͻ 25 years; p value ϭ .0418; if
8.105 21.76 to 26.24 minutes ␣ ϭ .025, do not reject H0
8.107 4.4 to 4.6 hours b. Critical value: z ϭ Ϫ1.96; observed value: z ϭ Ϫ1.73;
8.109 144.33 to 158.47 calories do not reject H0
8.111 a. .03 b. .014 to .046 9.39 a. H0: ␮ ϭ 10 minutes; H1: ␮ 10 minutes; test statistic:
8.113 6.1% to 56.4% z ϭ Ϫ2.11; p value ϭ .0348 If ␣ ϭ .02, do not reject H0. If
8.115 n ϭ 221 8.117 n ϭ 359 ␣ ϭ .05, reject H0. b. Observed value z ϭ Ϫ2.11;
8.121 n ϭ 65 If ␣ ϭ .02, critical values: z ϭ Ϫ2.33 and 2.33; do not
8.123 a. n ϭ 20 days b. 90% c. Ϯ75 cars reject H0. If ␣ ϭ .05, critical values: z ϭ Ϫ1.96 and 1.96;
reject H0.
9.41 a. test statistic: z ϭ Ϫ2.33; p value ϭ .0198;
Self-Review Test If ␣ ϭ .01; do not reject H0: If ␣ ϭ .05, reject H0.
1. a. population parameter; sample statistic b. Observed value z ϭ Ϫ2.33; If ␣ ϭ .01, critical values:
b. sample statistic; population parameter z ϭ Ϫ2.58 and 2.58, do not reject H0: If ␣ ϭ .05, critical
c. sample statistic; population parameter values: z ϭ Ϫ1.96 and 1.96; reject H0.
2. b 3. a 4. a 5. c 6. b 9.43 a. H0: ␮ ϭ 45.38 boxes; H1: ␮ Ͻ 45.38 boxes;
7. a. $159,000 z is Ϫ1.28. Ϫ.65; Do not reject H0
b. $147,390 to $170,610; margin of error ϭ Ϯ $11,610 b. do not reject H0.
8. $379,539.30 to $441,310.70 9. a. .55 9.45 a. H0: ␮ Ն 8 hours; H1: ␮ Ͻ 8 hours; critical value: z ϭ
b. .489 to .611 Ϫ2.33; ␣ ϭ .01; test statistic: z ϭ Ϫ.68; p value ϭ .2483
10. n ϭ 83 11. n ϭ 273 12. n ϭ 229 do not reject H0. b. critical value: z ϭ Ϫ1.96;
test statistic: z ϭ Ϫ.68; do not reject H0.
9.49 a. reject H0 if t Ͻ Ϫ2.977 or t Ͼ 2.977 b. reject H0
if t Ͻ Ϫ2.797 c. reject H0 if t Ͼ 2.080
Chapter 9 9.51 a. critical value: t ϭ Ϫ.68; 50 Ͻ p-value Ͻ .80.
9.5 a. a left-tailed test b. a right-tailed test t are Ϫ2.365 and 2.365. b. critical value:
c. a two-tailed test t ϭ Ϫ1.895; observed value: t ϭ Ϫ.68;
9.7 a. Type II error b. Type I error .5 Ͻ p-value Ͻ .8
9.9 a. H0: ␮ ϭ 20 hours; H1: ␮ 20 hours; two-tailed test 9.53 a. reject H0 if t Ͼ 1.672 b. reject H0 if t Ͻ Ϫ1.672
b. H0: ␮ ϭ 8 hours; H1: ␮ Ͼ 8 hours; right-tailed test c. reject H0 if t Ͻ Ϫ2.002 or t Ͼ 2.002
c. H0: ␮ ϭ 5 years; H1: ␮ 5 years; two-tailed test 9.55 a. critical value: t ϭ 1.998; test statistic: t ϭ 4.800;
d. H0: ␮ ϭ $1000; H1: ␮ Ͻ $1000; left-tailed test reject H0 b. critical value: t ϭ 1.998; test statistic:
e. H0: ␮ ϭ 15 minutes; t ϭ 1.143; do not reject H0
H1: ␮ Ͻ 15 minutes; left-tailed test 9.57 a. critical value: t ϭ Ϫ1.363; test statistic: t ϭϪ1.252;
9.17 a. p-value ϭ .0188 b. p-value ϭ .0116 do not reject H0 b. critical values: t ϭ Ϫ2.064 and
c. p-value ϭ .0087 2.064; test statistic: t ϭ 2.258; reject H0 c. critical
9.19 a. p-value ϭ .0166 b. no, do not reject H0 value: t ϭ 3.143; test statistic: t ϭ 2.658; do not
c. yes, reject H0 reject H0
9.21 a. rejection region is to the left of Ϫ2.58 and to the right 9.59 H0: ␮ р 4.145 minutes; H1: ␮ Ͼ 4.145 minutes;
of 2.58; nonrejection region is between Ϫ2.58 and 2.58 critical value: t ϭ 1.301; test statistic: t ϭ 1.862;
b. rejection region is to the left of Ϫ2.58; nonrejection reject H0; .025 Ͻ p value Ͻ .05; reject H0
region is to the right of Ϫ2.58 9.61 H0: ␮ ϭ $1050; H1: ␮ Ͻ $1050; critical value of t is
c. rejection region is to the right of 1.96; nonrejection Ϫ2.391; t ϭ Ϫ4.715; reject H0; if ␣ ϭ .025, the critical
region is to the left of 1.96 value for t is Ϫ2.001; reject H0
9.23 Statistically not significant 9.63 H0: ␮ ϭ 14.325 homes; H1: m 14.325 homes; test
9.25 a. .10 b. .02 c. .005 statistic: t ϭ Ϫ.752; p-value Ͼ .10; do not reject H0;
9.27 a. critical values of z are Ϫ1.96 and 1.96. z ϭ .21 for a ϭ.05, critical values: t ϭ Ϫ2.020 and t ϭ 2.020;
b. the critical value of z is 1.65. z ϭ .21 test statistic: t ϭ Ϫ.752; do not reject H0



9.65 a. H0: ␮ у $150; H1: ␮ Ͻ $150; test statistic: t ϭ Ϫ1.964; 9.107 a. H0: ␮ р 2400 square feet; H1: ␮ Ͼ 2400 square feet;
.025 Ͻ p-value Ͻ .050; do not reject H0; for ␣ ϭ .01, critical value: t ϭ 1.677; test statistic: t ϭ 2.097; reject H0
critical value: t ϭ Ϫ2.492; test statistic: t ϭ Ϫ1.964; do b. for ␣ ϭ .01 critical value: t ϭ 2.405; test statistic:
not reject H0 b. ␣ ϭ .01 t ϭ 2.097; do not reject H0
9.67 a. 58 years b. H0: ␮ ϭ 57 years, H1: ␮ 57 years; 9.109 H0: ␮ р 15 minutes; H1: ␮ Ͼ 15 minutes; critical value:
t ϭ Ϫ3.536; reject H0; p-value Ͻ .01; for ␣ ϭ .01, the t ϭ 2.438; test statistic: t ϭ 1.875; do not reject H0
critical values of t are Ϫ2.680 and 2.680; t ϭ Ϫ3.536; 9.111 H0: ␮ ϭ 25 minutes; H1: ␮ 25 minutes; critical values: t
reject H0 ϭ Ϫ2.947 and 2.947; test statistic: t ϭ 2.083; do not
9.69 H0: ␮ ϭ $95, H1: ␮ Ͼ $95; critical value of t is 1.796; reject H0
1.261; do not reject H0 9.113 a. H0: ␮ р 2 hours; H1: ␮ Ͼ 2 hours; critical value: t ϭ
9.71 H0: ␮ ϭ $3.084; H1: ␮ Ͻ $3.084; test statistic: 2.718; test statistic: t ϭ 1.679; do not reject H0
t ϭ Ϫ2.024; .01 Ͻ p value Ͻ .025; do not reject H0; 9.115 a. H0: p ϭ .5; H1: p .5; critical values: z ϭ Ϫ1.96
critical value: t ϭ Ϫ2.326; do not reject H0 and 1.96; test statistic: z ϭ 1.52; do not reject H0
9.75 a. not large enough b. large enough b. P(Type I error) ϭ .05 c. a ϭ .05; p-value ϭ
c. not large enough d. large enough .1286; do not reject H0.
9.77 a. reject H0 if z Ͻ Ϫ1.65 or z Ͼ 1.65 b. reject H0 if 9.117 H0: p ϭ .40; H1: p .40; critical values: z ϭ Ϫ2.58 and
z Ͻ Ϫ2.33 c. reject H0 if z Ͼ 1.65 2.58; test statistic: z ϭ Ϫ1.62; do not reject H0; p-value
ϭ .1052; do not reject H0
9.79 a. critical value: z ϭ 1.65; observed value: z ϭ 3.90
9.119 a. H0: p ϭ .80; H1: p Ͻ .80; critical value: z ϭ Ϫ2.33;
b. critical values: z ϭ Ϫ1.96 and 1.96; observed value:
test statistic: z ϭ Ϫ.79; do not reject H0
z ϭ 3.90
b. do not reject H0
9.81 a. reject H0 if z Ͻ Ϫ1.65 b. reject H0 if z Ͻ Ϫ1.96
9.121 a. .0238 b. ␣ ϭ .0238
or z Ͼ 1.96 c. reject H0 if z Ͼ 1.65
9.123 ␣ ϭ .3446
9.83 a. critical values: z ϭ Ϫ2.58 and 2.58; test statistic: z ϭ 9.125 H0: ␮ ϭ 750 hours; H1: ␮ Ͻ 750 hours; reject H0
Ϫ1.07; do not reject H0 b. critical values: z ϭ Ϫ2.58 if x Ͻ 735: ␣ ϭ .0082; reject H0 if x Ͻ 700: ␣ ϭ .0000
and 2.58; test statistic: z ϭ 3.21; reject H0 9.129 a. 29 or more, or 11 or less b. 226 or more, or 174
9.85 a. critical values: z ϭ Ϫ1.65 and 1.65; test statistic: or less c. 2081 or more, or 1919 or less
z ϭ .80; do not reject H0 b. critical value: z ϭ Ϫ1.65;
test statistic: z ϭ Ϫ4.71; reject H0 c. critical value:
z ϭ 2.33; test statistic: z ϭ .93; do not reject H0 Self-Review Test
9.87 H0: p ϭ .30; H1: p Ͻ .30; test statistic: z ϭϪ1.75; 1. a 2. b 3. a 4. b 5. a 6. a
p value ϭ .0401; for a ϭ.05, reject H0; critical value for 7. a 8. b 9. c 10. a 11. c 12. b
a ϭ.05: z ϭ Ϫ1.65; test statistic: z ϭ Ϫ1.75; reject H0 13. c 14. a 15. b
9.89 H0: p ϭ .67; H1: p Ͼ .67; critical value: z ϭ 2.05; test 16. a. H0: ␮ ϭ 90.25 ozs; H1: ␮ 90.25 ozs; critical values:
statistic: z ϭ 3.15; reject H0; p-value ϭ.0009; for a ϭ .02, z ϭ Ϫ2.58 and 2.58; test statistic: z ϭ Ϫ3.18; reject H0
reject H0 b. H0: ␮ ϭ 90.25 ozs; H1: ␮ Ͼ 90.25 ozs; critical value:
9.91 H0: p ϭ .231; H1 ϭ p Ͼ .231; critical value: z ϭ 1.65; z ϭ Ϫ1.96; test statistic: z ϭ Ϫ3.18; reject H0 c. in part a,
test statistic: z ϭ .97; do not reject H0; p value ϭ .1660; ␣ ϭ .01; in part b, ␣ ϭ .025 d. p-value ϭ .0014, reject
for a ϭ .05, do not reject H0 H0 e. p-value ϭ .0007, reject H0
9.93 a. H0: p Ն .35; H1: p Ͻ .35; critical value: z ϭ Ϫ1.96; 17. a. H0: ␮ ϭ 185; H1: ␮ Ͻ 185; critical value: t ϭ Ϫ2.438
test statistic: z ϭ Ϫ2.94; reject H0 b. do not reject H0 test statistic: t ϭ Ϫ3.000; reject H0 b. P(Type I error)
c. a ϭ .025; p value ϭ .0016; reject H0 ϭ .01 c. do not reject H0 d. .001 Ͻ p-value Ͻ
9.95 a. critical value: z ϭ 1.96; test statistic: z ϭ 2.27; .005; for ␣ ϭ .01, reject H0
reject H0; adjust machine b. critical value: z ϭ 2.33; 18. a. H0: ␮ Ն 31 months; H1: ␮ Ͻ 31 months; critical value:
test statistic: z ϭ 2.27; do not reject H0; do not adjust the t ϭ Ϫ2.131; test statistic: t ϭ Ϫ3.333; reject H0
machine b. P(Type I error) ϭ .025 c. critical value:
t ϭ Ϫ3.733; do not reject H0
9.99 a. critical value: z ϭ 1.96; test statistic: z ϭ 2.10; reject
19. a. H0: p ϭ .5; H1: p Ͻ .5; critical value: z ϭ Ϫ1.65; test
H0 b. P(Type I error) ϭ .025 c. p-value ϭ
statistic: z ϭ Ϫ3.16; reject H0 b. P(Type I error) ϭ .05
.0179; do not reject H0 if ␣ ϭ .01; reject H0 if ␣ ϭ .05
c. do not reject H0 d. p-value ϭ .0008; reject H0 if
9.101 a. critical values: z ϭ Ϫ2.33 and 2.33; test statistic:
␣ ϭ .05; reject H0 if ␣ ϭ .01
z ϭ 2.55; reject H0 b. P(Type I error) ϭ .02
c. p-value ϭ .0108; reject H0 if ␣ ϭ .025; do not reject
H0 if ␣ ϭ .005
9.103 a. H0: ␮ ϭ 67.2 minutes; H1: ␮ Ͼ 67.2 minutes; test
Chapter 10
statistic: z ϭ 4.98; p value Ͻ .0002; if a ϭ .05, reject H0 10.3 a. 3.49 b. 1.38 to 5.60
b. critical value: z ϭ 2.33; test statistic: z ϭ 4.98; reject 10.5 H0: ␮1 Ϫ ␮2 ϭ 0; H1: ␮1 Ϫ ␮2 0; critical values of z
H0 are Ϫ1.96 and 1.96; 4.26; reject H0 since 4.26 Ͼ 1.96
9.105 a. H0: ␮ ജ 50; H1: ␮ Ͻ 50; critical value of z ϭ Ϫ1.96; 10.7 H0: ␮1 Ϫ ␮2 ϭ 0, H1: ␮1 Ϫ ␮2 Ͻ 0; critical value of z is
test statistic: z ϭ Ϫ3.00; reject H0 Ϫ1.65; Ϫ1.52; do not reject H0
b. P(Type I error) ϭ .025 c. do not reject H0 10.9 a. 9 hours b. 1.65 to 16.35 hours; c. H0 :
d. p-value ϭ .0013; for ␣ ϭ .025, reject H0 ␮1 Ϫ ␮2 ϭ 0; H1: ␮1 Ϫ ␮2 0; critical values: z ϭ Ϫ2.33



and 2.33; test statistic: z ϭ 2.66; reject H0; p-value ϭ .0078; test statistic: t ϭ 7.252; reject H0 c. critical value:
for ␣ ϭ .02, reject H0 t ϭ Ϫ1.328; test statistic: t ϭ Ϫ14.389; reject H0
10.11 a. 1.83 ounce b. 1.45 to 2.21 ounces 10.53 a. 3.43 Ϯ 7.18 ϭ Ϫ3.75 to 10.61 minutes
c. H0: ␮1 Ϫ ␮2 ϭ 0, H1: ␮1 Ϫ ␮2 Ͼ 0; p-value Ϸ 0; b. H0: ␮d ϭ 0, H1: ␮d Ͼ 0; critical value of t is 2.447;
for a ϭ.01, the critical value of z is 2.33; z ϭ 9.52; t ϭ 1.770; do not reject H0
reject H0 10.55 a. 13.22 to 30.01 seconds b. H0: ␮d Ͻ ϩ15;
10.13 a. Ϫ$1024.54 to Ϫ$75.46 b. H0: ␮1 Ϫ ␮2 ϭ 0; H1: H1: ␮d ϩ15; critical value: t ϭ 1.356; test statistic:
␮1 Ϫ ␮2 0; critical values: z ϭ Ϫ2.58 and 2.58; test t ϭ 1.72, reject H0
statistic: z ϭ Ϫ2.99; reject H0 c. do not reject H0 10.57 a. Ϫ1.02 to 1.52 b. H0: ␮d ϭ 0; H1: md 0;
10.15 a. Ϫ6.87 to .87 calories b. H0: ␮1 Ϫ ␮2 ϭ 0; H1: critical values: t ϭ Ϫ2.093 and 2.093; test statistic:
␮1 Ϫ ␮2 Ͻ 0; critical value: z ϭ Ϫ2.58; test statistic: t ϭ .4122; do not reject H0
z ϭ Ϫ1.81; do not reject H0 c. p value ϭ .0351; do 10.61 Ϫ.062 to .142
not reject H0 for ␣ ϭ .005; do not reject H0 for ␣ ϭ .025 10.63 H0: p1 Ϫ p2 ϭ 0; H1: p1 Ϫ p2 0; critical values:
10.17 a. Ϫ3.93 b. Ϫ6.34 to Ϫ1.52 z ϭ Ϫ1.96 and 1.96; test statistic: z ϭ .76; do not
10.19 H0: ␮1 Ϫ ␮2 ϭ 0; H1: ␮1 Ϫ ␮2 0; critical values: t ϭ reject H0
Ϫ2.023 and 2.023; test statistic t ϭ Ϫ1.430; do not 10.65 H0: p1 Ϫ p2 ϭ 0; H1: p1 Ϫ p2 Ͼ 0; critical value:
reject H0 z ϭ 2.05; test statistic: z ϭ .76; do not reject H0
10.21 H0: ␮1 Ϫ ␮2 ϭ 0; H1: ␮1 Ϫ ␮2 Ͻ 0; critical value: 10.67 a. Ϫ.04 b. Ϫ.086 to .006 c. rejection region
t ϭ Ϫ2.426; test statistic: t ϭ Ϫ1.430; do not reject H0 to the left of z ϭ Ϫ2.33; non-rejection region to the right of
10.23 a. 2.96 b. Ϫ6.63 to 12.55 c. H0: ␮1 Ϫ ␮2 ϭ 0, z ϭ Ϫ2.33 d. test statistic: z ϭ Ϫ2.02 e. do not
H1: ␮1 Ϫ ␮2 Ͼ 0; critical value of t is 2.518; .778; do not reject H0
reject H0 10.69 a. Ϫ .025 to .225 b. H0: p1 Ϫ p2 ϭ 0; H1: p1 Ϫ p2
10.25 a. Ϫ46.80 to Ϫ7.20 miles; b. H0: ␮1 Ϫ ␮2 ϭ 0; Ͻ 0; critical values: z ϭ 1.96 and Ϫ1.96; test statistic:
H1: ␮1 Ϫ ␮2 Ͻ 0; critical value: t ϭ Ϫ2.326; z ϭ 1.56; do not reject H0; p value ϭ.1188; for a ϭ.025,
test statistic: t ϭ Ϫ2.67; reject H0 do not reject H0 c. .012 to .188; critical values: z ϭ
10.27 a. 3.92 to 8.08 mph b. H0: ␮1 Ϫ ␮2 ϭ 0, Ϫ1.96 and 1.96; test statistic: z ϭ 2.20; reject H0; p value
H1: ␮1 Ϫ ␮2 Ͼ 0; critical value of t is 2.410; 6.96; ϭ.0278; for a ϭ.05, reject H0
reject H0 10.71 a. .024 b. Ϫ.020 to .068 c. H0: p1 Ϫ p2 ϭ 0;
10.29 a. Ϫ11.94 to 1.94 minutes b. H0: ␮1 Ϫ ␮2 ϭ 0, H1: p1 Ϫ p2 0; critical values: z ϭ Ϫ1.96 and 1.96; test
H1: ␮1 Ϫ ␮2 Ͻ 0; critical value of t is Ϫ2.395; statistic: z ϭ 1.09; do not reject H0; p-value ϭ .2758; for
t ϭ Ϫ1.92; do not reject H0 ␣ ϭ .05, do not reject H0
10.31 a. Ϫ.61 to Ϫ.39 b. H0: ␮1 Ϫ ␮2 ϭ 0; H1: 10.73 a. .10 b. .018 to .182 c. H0: p1 Ϫ p2 ϭ 0;
␮1 Ϫ ␮2 0; critical values: t ϭ Ϫ2.576 and 2.576; test H1: p1 Ϫ p2 0; critical values: z ϭ Ϫ2.58 and 2.58; test
statistic: t ϭ Ϫ10.130; reject H0 statistic: z ϭ 3.04; reject H0
10.33 Ϫ7.86 to Ϫ1.04 10.75 a. Ϫ.013 to .093 b. H0: p1 Ϫ p2 ϭ 0;
10.35 H0: ␮1 Ϫ ␮2 ϭ 0; H1: ␮1 Ϫ ␮2 0; critical values: H1: p1 Ϫ p2 Ͼ 0; critical value: z ϭ 2.33 test statistic:
t ϭ Ϫ2.101 and 2.101; test statistic: t ϭ Ϫ2.740; do not z ϭ 1.75; do not reject H0
reject H0 10.77 a. Ϫ$119.16 to Ϫ$114.84 b. H0: ␮1 Ϫ ␮2 ϭ 0;
10.37 H0: ␮1 Ϫ ␮2 ϭ 0; H1: ␮1 Ϫ ␮2 Ͻ 0; critical value: H1: ␮1 Ϫ ␮2 Ͻ 0; critical value: z ϭ Ϫ1.96; test statistic:
t ϭ Ϫ2.552; test statistic: t ϭ Ϫ2.740; reject H0 z ϭ Ϫ106.25; reject H0
10.39 a. Ϫ47.01 to Ϫ6.99 miles; b. H0: ␮1 Ϫ ␮2 ϭ 0; 10.79 a. Ϫ.086 to .160 fatalities b. H0: ␮1 Ϫ ␮2 ϭ 0;
H1: ␮1 Ϫ ␮2 Ͻ 0; critical value: t ϭ Ϫ2.326; test statistic: H1: ␮1 Ϫ ␮2 Ͼ 0; critical value: t ϭ 2.326; test statistic:
t ϭ Ϫ2.64; reject H0 c. Ϫ48.30 to Ϫ5.70; critical t ϭ .70; do not reject H0
value: t ϭ Ϫ2.397; test statistic: t ϭ Ϫ2.54; reject H0 10.81 a. Ϫ8.42 to Ϫ1.82 cards b. H0: ␮1 Ϫ ␮2 ϭ 0;
10.41 a. 4.02 to 7.98 mph b. H0: ␮1 Ϫ ␮2 ϭ 0, H1: m1 Ϫ m2 0; critical values: t ϭ Ϫ1.645 and 1.645;
H1: ␮1 Ϫ ␮2 Ͼ 0; critical value of t is 2.418; t ϭ 7.34; test statistic: t ϭ Ϫ3.04; reject H0
reject H0 c. 3.82 to 8.18 mph; critical value of 10.83 a. Ϫ.085 to.159 fatalities; H0: ␮1 Ϫ ␮2 ϭ 0; H1: ␮1 Ϫ ␮2
t is 2.500; t ϭ 6.87; reject H0 Ͼ 0; critical value: t ϭ 2.326; test statistic: t ϭ .71; do not
10.43 a. Ϫ22.59 to 12.59 minutes b. H0: ␮1 Ϫ ␮2 ϭ 0, reject H0 b. Ϫ.076 to .150 fatalities; H0: ␮1 Ϫ
H1: ␮1 Ϫ ␮2 Ͻ 0; critical value of t is Ϫ2.408; t ϭ Ϫ.76; ␮2 ϭ 0; H1: ␮1 Ϫ ␮2 Ͼ 0; critical value: t ϭ 2.326; test
do not reject H0 c. Ϫ12.49 to 2.49 minutes; critical statistic: t ϭ .76; do not reject H0
value of t is Ϫ2.412; t ϭ Ϫ1.80; do not reject H0 10.85 a. Ϫ8.35 to Ϫ1.89 cards; H0: ␮1 Ϫ ␮2 ϭ 0; H1:
10.45 a. Ϫ.61 to Ϫ.39 b. H0: ␮1 Ϫ ␮2 ϭ 0; H1: m1 Ϫ m2 0; critical value: t ϭ Ϫ1.645 and 1.645; test
m1 Ϫ m2 0; critical values: t ϭ Ϫ2.576 and 2.576; test statistic: t ϭ Ϫ3.11; reject H0 b. Ϫ8.55 to Ϫ1.69
statistic: t ϭ Ϫ10.162; reject H0 c. Ϫ.62 to Ϫ.38; cards; H0: ␮1 Ϫ ␮2 ϭ 0; H1: m1 Ϫ m2 0; critical values:
critical values: t ϭ Ϫ2.576 and 2.576; test statistic: t ϭ Ϫ1.645 and 1.645; test statistic: t ϭ Ϫ2.93; reject H0
t ϭ Ϫ10.10; reject H0 10.87 a. Ϫ9.54 to Ϫ.24 b. H0: ␮d ϭ 0; H1:
10.49 a. 11.85 to 23.15 b. 50.08 to 61.72; c. 25.66 ␮d Ͻ 0; critical value: t ϭ Ϫ2.896; test statistic: t ϭ
to 32.94 Ϫ2.425; do not reject H0
10.51 a. critical values: t ϭ Ϫ2.060 and 2.060; test statistic: 10.89 a. Ind-Rep: Ϫ.106 to .046; Ind-Dem: .080 to .220; Rep-
t ϭ 12.551; reject H0 b. critical value: t ϭ 2.624; Dem: .103 to .257 b. H0: p1 Ϫ p2 ϭ 0; H1:



p1 Ϫ p2 0; critical values: z ϭ Ϫ2.58 and 2.58; test 11.43 a. H0: ␴ 2 ϭ 1.75; H1: ␴ 2 Ͼ 1.75
statistic: z ϭ Ϫ.77; do not reject H0 c. p value ϭ b. reject H0 if ␹ 2 Ͼ 34.170
.4412; for a ϭ .01, do not reject H0 c. test statistic: ␹ 2 ϭ 22.514
10.91 a. Ϫ.142 to Ϫ.018 b. H0: p1 Ϫ p2 ϭ 0; d. do not reject H0
H1: p1 Ϫ p2 0; critical values: z ϭ Ϫ1.96 and z ϭ 1.96; 11.45 a. H0: ␴ 2 ϭ 2.2; H1: ␴2 2.2 b. reject H0 if
test statistic: z ϭ Ϫ2.11; reject H0 ␹ 2 Ͻ 7.564 or ␹ 2 Ͼ 30.191 c. test statistic:
10.93 .2611 ␹ 2 ϭ 35.545 d. reject H0
10.95 nϭ9 11.47 a. .8120 to 3.3160; .9011 to 1.8210 b. H0: ␴ 2 Յ 1.0;
10.97 a. n ϭ 545 b. .8708 H1: ␴ Ͼ 1.0; critical value: ␹ ϭ 41.638; test statistic:
2 2

10.101 a. .3564 b. .0793 c. .0013 ␹ 2 ϭ 33.81; do not reject H0
11.49 a. 2739.3051 to 12,623.9126; 52.338 to 112.356
b. H0: ␴ 2 ϭ 4200; H1: ␴ 2 4200; critical values:
Self-Review Test ␹ 2 ϭ 12.401 and 39.364; test statistic: ␹ 2 ϭ 29.714; do not
1. a reject H0
3. a. 1.62 to 2.78 b. H0: ␮1 Ϫ ␮2 ϭ 0; H1: 11.51 critical value: ␹ 2 ϭ 7.815; test statistic: ␹ 2 ϭ 10.464;
␮1 Ϫ ␮2 Ͼ 0; critical value: z ϭ 1.96; test statistic: reject H0
z ϭ 9.86; reject H0 11.53 critical value: ␹ 2 ϭ 11.143; test statistic: ␹ 2 ϭ 22.359;
4. a. Ϫ2.72 to Ϫ1.88 hours b. H0: ␮1 Ϫ ␮2 ϭ 0; reject H0
H1: ␮1 Ϫ ␮2 Ͻ 0; critical value: t ϭ Ϫ2.416; test statistic: 11.55 critical value of ␹ 2 is 11.345; ␹ 2 ϭ 35.440; reject H0
t ϭ Ϫ10.997; reject H0 11.57 critical value: ␹ 2 ϭ 13,277; test statistic: ␹ 2 ϭ 50.355;
5. a. Ϫ2.70 to Ϫ1.90 hours b. H0: ␮1 Ϫ ␮2 ϭ 0; reject H0
H1: ␮1 Ϫ ␮2 Ͻ 0; critical value: t ϭ Ϫ2.421; test statistic: 11.59 critical value of ␹ 2 is 4.605; ␹ 2 ϭ 1.623; do not reject H0
t ϭ Ϫ11.474; reject H0 11.61 critical value: ␹ 2 ϭ 16.812; test statistic: ␹ 2 ϭ 10.181; do
6. a. Ϫ$53.60 to $186.18 b. H0: ␮d ϭ 0; H1: ␮d 0; not reject H0
critical values: t ϭ Ϫ2.447 and 2.447; test statistic: 11.63 a. 3.4064 to 24.0000; 1.846 to 4.899 b. 8.3336 to
t ϭ 2.050; do not reject H0 33.2628; 2.887 to 5.767
7. a. Ϫ.052 to .092 b. H0: p1 Ϫ p2 ϭ 0; 11.65 H0: ␴ 2 ϭ 1.1; H1: ␴ 2 Ͼ 1.1; critical value: ␹ 2 ϭ 28.845;
H1: p1 Ϫ p2 0; critical values: z ϭ Ϫ2.58 and 2.58; test statistic: ␹ 2 ϭ 24.727; do not reject H0
test statistic: z ϭ .60; do not reject H0 11.67 H0: ␴ 2 ϭ 10.4; H1: ␴ 2 10.4; critical values: ␹ 2 ϭ 7.564
and 30.191; test statistic: ␹ 2 ϭ 24.192; do not reject H0
11.69 a. H0: ␴ 2 ϭ 5000; H1: ␴ 2 Ͻ 5000; critical value:
Chapter 11 ␹ 2 ϭ 8.907; test statistic: ␹ 2 ϭ 12.065; do not reject H0
b. 1666.8509 to 7903.1835; 40.827 to 88.900
11.3 ␹ 2 ϭ 36.415 11.5 ␹ 2 ϭ 48.278 11.71 a. .1001 to .4613; .316 to .679 b. H0: ␴ 2 ϭ .13; H1:
11.7 a. ␹ ϭ 3.571 b. ␹ 2 ϭ 3.074
2
␴ 2
.13; critical values: ␹ ϭ 9.886 and 45.559; test
2

11.13 critical value of ␹ 2 is 11.070; ␹ 2 ϭ 11.000; statistic: ␹ 2 ϭ 35.077; do not reject H0
do not reject H0 11.73 a. s2 ϭ 1963.642857 b. 858.3963 to 8133.4320;
11.15 critical value: ␹ 2 ϭ 7.815; test statistic: ␹ 2 ϭ 45.844; 29.30 to 90.19 c. H0: ␴2 ϭ 750; H1: s2 750;
reject H0 ␹ 2 ϭ 18.327; reject H0
11.17 critical value of ␹ 2 is 13.277; ␹ 2 ϭ 47.469; reject H0 11.75 critical value: ␹ 2 ϭ 5.991; test statistic: ␹ 2 ϭ 12.931;
11.19 critical value of ␹ 2 is 9.488; ␹ 2 ϭ 19.300; reject H0 reject H0
11.21 critical value: ␹ 2 ϭ 9.348; test statistic: ␹ 2 ϭ 65.087; reject 11.77 critical value: ␹ 2 ϭ 9.488; test statistic: ␹ 2 ϭ 6.857;
H0 do not reject H0
11.27 a. H0: the proportion in each row is the same for all four 11.79 critical value: ␹ 2 ϭ 16.919; test statistic: ␹ 2 ϭ 215.568;
populations. reject H0
H1: the proportion in each row is not the same for all four 11.81 a. test statistic: ␹ 2 ϭ 2.480; p-value Ͼ .10 b. no
populations.
c. critical value of ␹ 2 is 14.449 d. ␹ 2 ϭ 61.179
e. reject H0
11.29 critical value of ␹ 2 is 5.024; ␹ 2 ϭ 1.069; do not reject H0 Self-Review Test
11.31 a. critical value: ␹ 2 ϭ 6.635; test statistic: ␹ 2 ϭ 8.647; 1. b 2. a 3. c 4. a 5. b 6. b
reject H0 b. critical value: x2 ϭ 6.635; test statistic: 7. c 8. b 9. a
x ϭ 17.317; reject H0
2
10. critical value: ␹ 2 ϭ 11.070; test statistic: ␹ 2 ϭ 20.146; reject
11.33 critical value of ␹ 2 is 7.815; ␹ 2 ϭ 5.806; do not reject H0 H0
11.35 critical value of ␹ 2 is 6.635; ␹ 2 ϭ 18.597; reject H0 11. critical value: ␹ 2 ϭ 11.345; test statistic: ␹ 2 ϭ 31.188; reject
11.37 critical value: ␹ 2 ϭ 7.815; test statistic: ␹ 2 ϭ 8.221; H0
reject H0 12. critical value: ␹ 2 ϭ 9.488; test statistic: ␹ 2 ϭ 82.450; reject
11.39 critical value: ␹ 2 ϭ 7.378; test statistic: ␹ 2 ϭ 2.404; do not H0
reject H0 13. a. .2364 to 1.3326; .486 to 1.154 b. H0: ␴ 2 ϭ .25;
11.41 a. 18.4376 to 84.9686 b. 21.3393 to 67.7365 H1: ␴ 2 Ͼ .25; critical value: ␹ 2 ϭ 36.191; test statistic:
c. 23.0674 to 60.6586 ␹ 2 ϭ 36.480; reject H0



Chapter 12 13.41 a. se ϭ 31.2410 b. r2 ϭ .45
13.43 a. se ϭ .9930 b. r2 ϭ .63
12.3 a. 6.06 b. 4.43 c. 4.00 13.45 a. ␴⑀ ϭ 68.1073 b. ␳2 ϭ .02
12.5 a. 5.39 b. 2.32 c. 1.61 13.47 a. 6.01 to 6.63 b. H0: B ϭ 0; H1: B Ͼ 0; critical
12.7 a. 9.96 b. 6.57 12.9 a. 4.85 b. 3.22 value: t ϭ 2.145; test statistic: t ϭ 59.792; reject H0
12.13 a. x1 ϭ 14.857; s1 ϭ 5.2734736; x2 ϭ 10.714; s2 ϭ c. H0: B ϭ 0; H1: B 0; critical values: t ϭ Ϫ2.977
5.023753103 b. H0: ␮1 Ϫ ␮2 ϭ 0, H1: m1 Ϫ m2 0; and 2.977; test statistic: t ϭ 59.792; reject H0 d. H0:
t are Ϫ2.179 and 2.179; t ϭ 1.505; do not reject H0 B ϭ 4.50; H1: B 4.50; critical values: t ϭ Ϫ2.624 and
c. critical value of F is 4.75; F ϭ 2.26; do not reject H0 2.624; test statistic: t ϭ 17.219; reject H0
d. conclude are equal 13.49 a. 2.35 to 2.65 b. H0: B ϭ 0; H1: B Ͼ 0; critical
12.15 b. critical value: F ϭ 3.29; test statistic: F ϭ 4.07; reject value: t ϭ 1.960; test statistic: t ϭ 39.124; reject H0;
H0 c. H0: B ϭ 0; H1: B 0; critical values: t ϭ Ϫ2.576
12.17 a. H0: ␮1 ϭ ␮2 ϭ ␮3 ϭ ␮4; H1: all four population means and 2.576; test statistic: t ϭ 39.124; reject H0;
are not equal b. numerator: df ϭ 3; denominator: d. H0: B Յ 1.75; H1: B Ͼ 1.75; critical value:
df ϭ 28 c. SSB ϭ.0105; SSW ϭ 1.1449; SST ϭ t ϭ 2.326; test statistic: t ϭ 11.737; reject H0
1.1554 d. reject H0 if F Ͼ 4.58 e. MSB ϭ 13.51 a. Ϫ39.4166 to Ϫ28.7574 b. H0: B ϭ 0; H1: B Ͻ 0;
.0035; MSW ϭ .0409 f. critical value: F ϭ 4.58 critical value of t is Ϫ1.943; Ϫ15.651; reject H0
g. test statistic: F ϭ .0856 i. do not reject H0 13.53 a. y ϭ 2.4377x ϩ 25.5536
ˆ b. 1.331 to 3.5443
12.19 critical value: F ϭ 3.55; test statistic: F ϭ 2.09; do not c. H0: B ϭ 0; H1: B Ͼ 0; critical value: t ϭ 2.365; test
reject H0 statistic: t ϭ 6.6042; reject H0
12.21 critical value: F ϭ 3.72; test statistic: F ϭ 5.44; reject H0 13.55 a. Ϫ30.5005 to Ϫ20.2424 b. H0: B ϭ 0; H1: B Ͻ 0;
12.23 a. critical value: F ϭ 2.05; test statistic: F ϭ 2.12; critical value: t ϭ Ϫ2.764; test statistic: t ϭ Ϫ15.6759;
reject H0 b. .10 reject H0
12.25 a. critical value: F ϭ 6.93; test statistic: F ϭ 1.24; do not 13.57 a. y ϭ 4.7844 ϩ 1.1354x
ˆ b. .6684 to 1.6024
reject H0 c. H0: B ϭ 1.0; H1: B 1.0; critical values of t are
12.27 a. critical value: F ϭ 3.89; test statistic: F ϭ 4.89; reject Ϫ2.228 and 2.228; t ϭ .646; do not reject H0
H0 b. do not reject H0 13.63 a 13.67 a. positive b. positive
12.29 critical value: F is 5.29; test statistic: F ϭ.57; do not c. positive d. negative e. zero
reject H0 13.69 ␳ ϭ .21
12.33 a. 5 groups with 10 members each. b. 36 members 13.71 a. r ϭ Ϫ.996 b. H0: ␳ ϭ 0; H1: ␳ Ͻ 0; critical
each. value: t ϭ Ϫ2.764; test statistic: t ϭ Ϫ35.249; reject H0
13.73 a. positively b. r ϭ .93 c. H0: ␳ ϭ 0;
Self-Review Test H1: ␳ Ͼ 0; critical value: t ϭ 1.895; test statistic:
t ϭ 6.694; reject H0
1. a 2. b 3. c 4. a 5. a
13.75 a. positively b. close to 1 c. r ϭ .97
6. a 7. b 8. a
d. H0: ␳ ϭ 0; H1: ␳ 0; critical values: t ϭ Ϫ2.776 and
10. a. critical value: F ϭ 3.10; test statistic: F ϭ 4.46; reject H0
2.776; test statistic: t ϭ 7.980; reject H0
b. Type I error
13.77 a. r ϭ .93 b. H0: ␳ ϭ 0; H1: ␳ 0; critical values:
t ϭ Ϫ3.499 and 3.499; test statistic: t ϭ 6.694;
reject H0
Chapter 13 13.79 ␳ ϭ .16
13.15 a. y-intercept is 80; slope is Ϫ3; negative relationship 13.81 a. SSxx ϭ 750; SSyy ϭ 2502.6667; SSxy ϭ 710
b. y-intercept is 250; slope is 8; positive relationship b. y ϭ 24.8 ϩ .9467x
ˆ d. r ϭ .52; r2 ϭ .27
13.17 my0x ϭ Ϫ3.3921 ϩ .2370x f. $93.91 g. se ϭ 13.5297 h. Ϫ.15 to 2.05
13.19 y ϭ 5.143 ϩ 2.2857x
ˆ i. H0: B ϭ 0; H1: B Ͼ 0; critical value: t ϭ 1.812; test
13.21 a. 90 b. same amount statistic: t ϭ 1.916; reject H0 j. H0: ␳ ϭ 0; H1:
c. relationship is exact ␳ Ͼ 0; critical value: t ϭ 2.228; test statistic:
13.23 a. 38.85 b. differ t ϭ 1.925; do not reject H0
c. relationship is nonexact 13.83 a. SSxx ϭ 6394.9; SSyy ϭ 1718.9; SSxy ϭ 3136.1
13.25 b. y ϭ 317.6959 Ϫ 34.0870x
ˆ c. $3408.70 b. y ϭ Ϫ22.5355 ϩ .4904x
ˆ d. r ϭ .95; r2 ϭ .89
f. Ϫ295.8701 e. se ϭ 4.7557 f. .291 to .690 g. H0: B ϭ 0;
13.27 b. y ϭ 191.6238 Ϫ 25.3714x
ˆ e. 112.9724 H1: B Ͼ 0; critical value: t ϭ 2.896; test statistic: t ϭ 8.246;
f. Ϫ62.0905 reject H0 h. H0: ␳ ϭ 0; H1: ␳ 0; critical values:
13.29 a. my0x ϭ 630.6627 ϩ 1.2289x b. population t ϭ Ϫ3.355 and 3.355; test statistic: t ϭ 8.605; reject H0
regression line because data set includes all 16 National 13.85 a. SSxx ϭ 3.3647; SSyy ϭ 788; SSxy ϭ 49.4
League teams; values of A and B d. 734 runs b. y ϭ 2.8562 ϩ 14.6819x
ˆ d. r ϭ .96;
13.35 ␴⑀ ϭ 7.0756; ␳2 ϭ .04 r 2 ϭ .92 e. se ϭ 3.5416 f. 9.718 to 19.646
13.37 se ϭ 63.099; r2 ϭ Ϫ.44 g. H0: B ϭ 0; H1: B 0; critical values:
13.39 a. SSxx ϭ 64; SSyy ϭ 93636.8889; SSxy ϭ 2283.8 t ϭ Ϫ4.032 and 4.032; test statistic: t ϭ 7.6043;
b. se ϭ 41.6463 c. SST ϭ 93636.8889; SSE ϭ reject H0 h. H0: ␳ ϭ 0; H1: ␳ Ͼ 0; critical value:
12140.9133; SSR ϭ 81495.9756 d. r2 ϭ .87 t ϭ 3.365; test statistic: t ϭ 7.6665; reject H0



13.87 a. 13.8708 to 16.6292; 11.7648 to 18.7352 Self-Review Test
b. 62.3590 to 67.7210; 56.3623 to 73.7177
1. d 2. a 3. b 4. a 5. b 6. b
13.89 $4611.38 to $5374.78; $3808.78 to $6177.38
7. true 8. true 9. a 10. b
13.91 $77.63 to $95.03; $54.96 to $117.71
15. a. The attendence depends on temperature.
13.93 $1518.85 to $2212.88; $715.60 to $3016.13
b. positive d. y ϭ Ϫ2.2269 ϩ .2715x
ˆ
13.95 a. positive relationship
f. r ϭ .65; r ϭ .42
2
g. 1407 people
b. y ϭ Ϫ1.9172 ϩ .9895x
ˆ d. r ϭ .97; r2 ϭ .94
h. se ϭ 3.6172 i. Ϫ.30 to .84
e. se ϭ 1.0941 f. .54 to 1.44
j. H0: B ϭ 0; H1: B Ͼ 0; critical value: t ϭ 3.365;
g. H0: B ϭ 0; H1: B Ͼ 0; critical value: t ϭ 2.571; test
test statistic: t ϭ 1.904; do not reject H0
statistic: t ϭ 8.808; reject H0 h. H0: ␳ ϭ 0; H1: ␳ Ͼ 0;
k. 1055 to 1758 l. 412 to 2401
critical value: t ϭ 2.571; test statistic: t ϭ 8.922; reject
m. H0: ␳ ϭ 0; H1: ␳ Ͼ 0; critical value: t ϭ 3.365;
H0; same conclusion
test statistic: t ϭ 1.913; do not reject H0
13.97 a. positive b. y ϭ 7.8304 ϩ .5039x
ˆ
d. r ϭ .89; r 2 ϭ .79 e. 2547 f. se ϭ 3.3525
g. .11 to .90 h. H0: B ϭ 0; H1: B Ͼ 0; critical Appendix A
value: t ϭ 3.365; test statistic: t ϭ 4.278; reject H0
i. H0: ␳ ϭ 0; H1: ␳ 0; critical values: t ϭ Ϫ3.365 and A.7 simple random sample A.9 a. nonrandom sample
3.365; test statistic: t ϭ 4.365; reject H0 b. judgment sample c. selection error
13.99 a. SSxx ϭ 144.32; SSyy ϭ 3.02329; SSxy ϭ Ϫ1.356 A.11 a. random sample b. simple random sample
b. slightly yes c. y ϭ Ϫ.2133 Ϫ .0094x
ˆ c. no
e. r ϭ Ϫ.06 f. Ϫ$.29 A.13 a. nonrandom sample b. voluntary response error
13.101 b. Sxx ϭ 82.5; SSyy ϭ.88956; SSxy ϭ Ϫ3.84 and selection error
c. yes d. y ϭ 22.1615 Ϫ .0465x
ˆ f. r ϭ Ϫ.45 A.15 response error
g. 21.65 seconds A.17 a. designed experiment b. no; would need to know if
13.103 60.7339 to 97.3729; 40.0144 to 118.0924 the women or the doctors who evaluated their health knew
13.105 1042.7081 to 1153.1345; 953.3648 to 1242.4778 which women took aspirin and which were in the control group
13.107 a. yes b. 246.4670 to 275.5330 lines A.19 a. designed experiment b. double-blind study

B n
c. 200.0567 to 321.9433 lines e. 338 lines A.21 designed experiment A.23 yes
13.111 a. increase b. decrease c. increase A.25 b. observational study c. not a double-blind study
nϩ1 A.27 a. designed experiment b. double-blind study
d. Ϯt . se A.29 a. no b. no c. convenience sample
A.33 a. no b. nonresponse error and response error
13.113 a. r ϭ .92; yes
c. above

Answers section a1-a12

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