Answers - Bloomsburg University of Pennsylvania

1

Answers

Chapter 1

Sections 1.1?1.2

1.1 (a) Descriptive. (b) Inferential. (c) Inferential. (d) Inferential. (e) Descriptive. (f ) Descriptive.

1.2 (a) Descriptive. (b) Inferential. (c) Descriptive. (d) Inferential. (e) Descriptive.

1.3 (a) Open heart patients operated on in the last year. (b) 30 patients selected. (c) Length of stay.

1.4 (a) People who wear T-shirts. (b) 50 people selected. (c) Whether they cut off the tag or not.

1.5 Population: employees at Citigroup Inc. Sample: 35 employees selected.

1.6 Population: Texas residents. Sample: 500 people from Texas selected.

1.7 Population: 10,000 families affected by the flood. Sample: 75 affected families selected.

1.8 (a) Population: All people who purchase a dining room table. Sample: 5 people selected at random. Probability question. (b) Population: All people entering the rest area and food court. Sample: 25 people selected. Statistics question. (c) Population: All people who use the slide. Sample: 50 people selected at random. Probability question. (d) Population: All doors that open automatically. Sample: 100 doors selected. Statistics question. (e) Population: All people entering LAX. Sample: 1000 people selected. Statistics question. (f ) Population: All women. Sample: 34 selected. Probability question. (g) Population: Two populations - two types of nursing homes. Sample: Several nursing homes selected. Statistics question.

1.9 (a) Population: all cheddar cheeses. Sample: 20 cheddar cheeses selected. (b) Probability question: What is the probability at least 10 of the cheddar cheeses selected are aged less than two years? Statistics questions: Suppose 12 of the cheddar cheeses selected are aged less than two years. Does this suggest that the true proportion of all cheddars aged less than two years has decreased?

1.10 (a) Population: All television households in the United States. Sample: 500 TV households selected. (b) Probability question: What is the probability at most 400 of the TV households selected have at least one DVD player? Statistics question: Estimate the true proportion of TV households that have at least one DVD player.

1.11 (a) Population: All Americans. (b) Sample: 1000 Americans selected. (c) Variable: Whether or not each believes sharks are dangerous.

1.12 (a) Population: All American companies. (b) Sample: 75 companies selected. (c) Variable: Whether each company has overseas IT workers. (d) Probability question: What is the probability exactly 30 of the 75 companies selected have overseas IT workers? Statistics question: Use the resulting data to determine if there is evidence the proportion of companies with overseas IT workers has changed.

1.13 Population: All shampoos. Sample: 20 shampoos selected. Variable: Amount of sulfur in each shampoo.

1.14 Population: People diagnosed with hepatitis C. Sample: 50 patients selected. Variable: Liver enzyme levels.

1.15 (a) Population: All Bounty paper towel rolls. (b) Sample: 35 rolls selected. (c) Variable: Amount of absorption.

Section 1.3

1.16 (a) Observational study. (b) Sample: The students who respond to the questions. (c) Not a random sample, only one dorm.

1.17 (a) Observational study. (b) Sample: 25 volunteer fire companies selected. (c) Not a random sample, largest companies selected.

1.18 (a) Population: All 12-ounce bottles of soda. Sample: The bottles selected. (b) Yes, a simple random sample.

1.19 Assign a number to each shipped weather station. Select numbers using a random number generator and examine each weather station corresponding to the numbers selected.

1.20 (a) Observational study. (b) Population: All Massachusetts State Police. Sample: 12 officers selected. (c) Not a random sample, only 1 shift considered.

1.21 (a) Population: All men who use a disposable razor. Sample: 100 men selected. (b) Not a random sample. Just selected men observed buying a razor.

1.22 Obtain a list of people who have purchased this product, and assign a number to each person. Randomly select numbers from a random number table or random number generator, and ask each corresponding customer how long it took to set up the fence.

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1.23 Assign a number to each challenge. Randomly select numbers from a random number table or random number generator.

1.24 (a) Assign a number to each mile-long stretch. Randomly select numbers from a random number table or random number generator. (b) Observational study.

1.25 (a) Experimental study. (b) Variable: Lifetime of each blossom. (c) Flip a coin: heads is treated, tails is untreated.

1.26 (a) Experimental study. (b) Variable: Which car is most comfortable. (c) Conversation with the driver, peeking, sound of the engine, legroom.

1.27 (a) Population: All ceramic tile from this manufacturer. Sample: 25 tiles selected. (b) Not a random sample. All tiles from the same box.

1.28 (a) Observational study. (b) Variables: proportion of white feathers, proportion of down, proportion of other components. (c) Randomly select stores from around the country that sell comforters. Visit the selected stores, and randomly purchase comforters on display.

Chapter 2 Section 2.1

2.1 (a) Numerical, continuous. (b) Numerical, discrete. (c) Categorical. (d) Numerical, discrete. (e) Numerical, continuous. (f ) Categorical.

2.2 (a) Numerical, continuous. (b) Numerical, discrete. (c) Numerical, continuous. (d) Numerical, continuous. (e) Categorical. (f ) Categorical.

2.3 (a) Numerical, discrete. (b) Numerical, discrete. (c) Categorical. (d) Numerical, continuous. (e) Numerical, continuous. (f ) Categorical.

2.4 (a) Numerical, discrete. (b) Numerical, continuous. (c) Categorical. (d) Categorical. (e) Categorical. (f ) Numerical, discrete.

2.5 (a) Continuous. (b) Continuous. (c) Discrete. (d) Continuous. (e) Continuous. (f ) Discrete.

2.6 (a) Continuous. (b) Continuous. (c) Discrete. (d) Continuous. (e) Continuous. (f ) Discrete.

2.7 (a) Continuous. (b) Discrete. (c) Discrete. (d) Continuous. (e) Discrete. (f ) Discrete.

2.8 (a) Continuous. (b) Discrete. (c) Continuous. (d) Discrete. (e) Categorical. (f ) Categorical.

2.9 (a) Discrete. (b) Categorical. (c) Continuous. (d) Continuous. (e) Categorical. (f ) Continuous.

Section 2.2

2.10

Relative

Category Frequency Frequency

Comedy

7

Drama

10

Educational

3

Reality

7

Soap

10

Sports

5

0.1667 0.2381 0.0714 0.1667 0.2381 0.1190

Total

42

1.0000

2.11 Art

Relative Frequency Frequency

Abstract

15

Expressionist

6

Realist

12

Surrealist

9

0.3571 0.1429 0.2857 0.2143

Total

42

1.0000

2.12 Class

Relative Frequency Frequency

Bally's

40

Caesars

25

Harrah's

32

Resorts

22

Sands

25

Trump Plaza 56

0.200 0.125 0.160 0.110 0.125 0.280

Total

200

1.000

(a) 200 (b) Trump Plaza: largest (relative) frequency.

2.13

(a) Issue

Relative Frequency Frequency

Salary

50

Health Insurance

100

Retirement Benefits 75

Class Size

60

Temporary Faculty

90

Parking

25

0.1250 0.2500 0.1875 0.1500 0.2250 0.6250

Total

400

1.0000

(b) 120

100

80

Frequency

60

40

20

0 Sal HI RB CS TF Park

Issue

2.14

(a) County

Relative Frequency Frequency

Adair Carroll Chariton Grundy Linn Livingston Macon Mercer Putnam Schuyler Sullivan

915 1081 1095

735 969 903 1351 569 723 480 850

0.0946 0.1118 0.1132 0.0760 0.1002 0.0934 0.1397 0.0588 0.0748 0.0496 0.0879

Total

9671

1.0000

(b) 0.150

0.125

0.100

Frequency

0.075

0.050

0.025

0.000

A Ca Ch G Li Lv Ma Me P Sc Su

County

2.15

(a)

Relative

Answer Frequency Frequency

VL

8

0.16

L

12

0.24

N

7

0.14

U

8

0.16

VU

15

0.30

Total

50

1.00

(b)

Likely

PSfrag replacements Neutral

Very Likely

Unlikely

Very Unlikely

3

2.16

(a) Political

Relative

affiliation Frequency Frequency

D

23

0.3833

I

19

0.3167

R

18

0.3000

Total

60

1.0000

(b)

Democrat

PSfrag reIpnldaecpemenednetnst

Republican

2.17

(a) Country

Relative Frequency Frequency

United States

270

United Kingdom 101

Germany

76

France

49

Sweden

30

Switzerland

22

All others

130

0.3982 0.1490 0.1121 0.0723 0.0442 0.0324 0.1917

Total

678

1.0000

PSfr(abg)replacements

United States

United Kingdom

Germany

All others

2.18

(a) Grade

France

Switzerland

Sweden

Relative Frequency frequency

A

10

0.0676

B

43

0.2905

C

54

0.3549

D

26

0.1757

F

15

0.1014

Total

148

1.0000

4

Frequency Frequency

Frequency

(b) 60

50 40 30 20 10

0

A

B

C

D

F

Grade

B

PSfrag replacements A

C

E

D (c) 148; 0.8986

2.19

(a) Ice Cream

Relative Frequency frequency

The Big Dig

20

Cashew Turtle

37

Chocolate Chip

52

Pistachio

30

Strawberry

16

Vanilla with Oreos 45

0.100 0.185 0.260 0.150 0.080 0.225

Total

200

1.000

(b)

50

40

30

20

10

0 Big Dig C Tur CC Pist Straw Van

Ice Cream

Cashew Turtle

PSfragCrheopcloalcaetme eCnhtsip

The Big Dig

2.20

(a) Agency

Relative Frequency frequency

Alamo

10

Avis

25

Budget

30

Enterprise 40

Hertz

35

Thrifty

20

Value

15

0.0571 0.1429 0.1714 0.2286 0.2000 0.1143 0.0857

Total

175

1.0000

(b) 175 (c) 0.5714 PSfr(adg)replacements Budget

Avis

Enterprise

Alamo Value

Hertz

Thrifty

2.21

(a)

Relative

Response Frequency frequency

Excellent

50

Very Good 152

Good

255

Fair

425

Poor

118

0.0500 0.1520 0.4250 0.4250 0.1180

Total

1000 1.0000

(b) 500

400

300

200

100

0

Ex

VG Good Fair Poor

Response

Good

Very Good

PSfrag replacements

Excellent

Poor

Pistachio

Vanilla with Oreos

Fair

Strawberry

(c) 0.7980

2.22

(a) Table saw

Relative

brand Frequency frequency

B&D

4

Craftsman

5

Delta

6

DeWalt

7

Makita

6

0.1429 0.1786 0.2143 0.2500 0.2143

Total

28

1.0000

Frequency

(b) 8

7 6 5 4 3 2 1 0

BD Craft Delta DeWalt Makita

Table saw brand Craftsman

PSfrag replacemDenelttsa

Black & Decker

DeWalt

(c) 0.3214 (d) 0.7857

2.23

(a) Year

Relative frequency

2000 2001 2002 2003 2004

0.2564 0.3298 0.4162 0.5229 0.8671

Makita

Relative Frequency

0.8

0.6

0.4

0.2

0 2000 2001 2002 2003 2004

Year

5

(b) Year

2000 2001 2002 2003 2004

Relative frequency

0.0039 0.0040 0.0056 0.0055 0.0099

0.01

Relative Frequency

0.008

0.006

0.004

0.002

0 2000 2001 2002 2003 2004

Year (c) Both graphs show an increase, each with a large jump in 2004.

2.24 (a) Product

Frequency

Alarms

75

Training

16

Extinguishers

13

Pumps

6

Sprinklers

16

Building Materials

19

Electrical Equipment

32

Hazmat Storage

22

Security Products

41

Signaling Systems

13

(b) 0.3

Relative Frequency

0.2

0.1

0 Al Tr Ex Pu Sp BM EE HS SP SS

Product

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