There is a relationship between smoking cigarettes and getting emphysema.

the number of seats in a movie theater

hair color of women on a high school tennis team

number of milligrams of tar in 85 cigarettes

the ratings of a movie ranging from “poor” to “good” to “excellent”

the final grades (A, B, C, D, and F) for students in a statistics class

the nationalities listed in a recent survey (for example, Asian, European, or Hispanic).

manuscripts rated “acceptable” or “unacceptable”

the lengths (in minutes) of the top ten movies with respect to ticket sales in 2007

A study where a drug was given to 23 patients and a placebo to another group of 23 patients to determine if the drug has an effect on a patient’s illness

A study where you would like to determine the chance getting three girls in a family of three children

Every fifth person boarding a plane is searched thoroughly.

A researcher for an airline interviews all of the passengers on five randomly selected flights.

A lobbyist for a major airspace firm assigns a number to each legislator and then uses a computer to randomly generate ten numbers. The lobbyist contacts the legislators corresponding to these numbers.

A market researcher randomly selects 200 drivers under 55 years of age and 200 drivers over 55 years of age.

A researcher randomly selected 25 of the nation’s middle schools and interviewed all of the teachers at each school.

The average age of the students in a statistics class is 22 years. Does this statement describe:

Based on previous clients, a marriage counselor concludes that the majority of marriages that begin with cohabitation before marriage will result in divorce. Does this statement describe inferential statistics or descriptive statistics?

Classify the number of seats in a movie theater as qualitative data or quantitative data.

Identify the level of measurement for data that are the temperature of 90 refrigerators.

Identify the level of measurement for data that are the number of milligrams of tar in 79 cigarettes.

Identify the level of measurement for data that are the ratings of a movie ranging from poor to good to excellent.

Identify the level of measurement for data that are the nationalities listed in a recent survey (for example, Asian, European, or Hispanic).

The numbers of touchdowns scored by a major university in five randomly selected games are given below. Identify the level of measurement.

1 5 4 5 5

What method of data collection would you use to collect data for a study where a political pollster wishes to determine if his candidate is leading in the polls?

At a local community college, five statistics classes are randomly selected and all of the students from each class are interviewed. What sampling technique is used?

A community college student interviews everyone in a statistics class to determine who owns a car. What sampling technique is used?

A lobbyist for a major airspace firm assigns a number to each legislator and then uses a computer to randomly generate ten numbers. The lobbyist contacts the legislators corresponding to these numbers. What sampling technique was used?

A market researcher randomly selects 200 drivers under 35 years of age and 100 drivers over 35 years of age. What sampling technique was used?

The names of 70 contestants are written on 70 cards. The cards are placed in a bag, and three names are picked from the bag. What sampling technique was used?

What method of data collection would you use to collect data for a study where you would like to determine the chance getting three girls in a family of three children?

(a) class width.

(b) class midpoints of the first class.

(c) class boundaries of the first class.

Phone Calls (per day)

(a) 3

(b) 9.5

(c) 7.5-11.5

(a) 3

(b) 10.5

(c) 8-11

(a) 4

(b) 10.5

(c) 8-11

(a) 4

(b) 9.5

(c) 7.5-11.5

(b) 9.5

(c) 7.5-11.5

Use the ogive below to approximate the cumulative frequency for 24 hours.

Student Answer:

75

27

17

63

Data set: California Pick Three Lottery

8 6 7 6 0 9 1 7 8 4

1 5 7 5 9 7 5 3 9 9

8 8 3 9 8 8 9 0 2 7

skewed right

symmetric

uniform

skewed left

Use the histogram below to approximate the mode heart rate of adults in the gym.

a) 70

b) 2

c) 55

d) 42

The top 14 speeds, in miles per hour, for Pro-Stock drag racing over the past two decades are listed below. Find the median speed.

118.1 202.2 190.1 201.4 191.3 201.4 192.2 201.2 193.2 201.2 194.5 199.2 196.0 196.2

195.8

201.2

196.7

196.1

The scores of the top ten finishers in a recent golf tournament are listed below. Find the median score.

67 67 68 71 72 72 72 72 73 76

Grade points are assigned as follows: A = 4, B = 3, C = 2, D = 1, and F = O. Grades are weighted according to credit hours. If a student receives an A in a four-unit class, a D in a two-unit class, a B in a three-unit class and a C in a three-unit class, what is the student’s grade point average?

The lengths of phone calls from one household (in minutes) were 2, 4, 6, 7, and 8 minutes. Find the midrange for this data.

2 minutes

5 minutes

6 minutes

10 minutes

Find the range of the data set represented by the graph.

6

20

5

17

Find the sample standard deviation.

2 6 15 9 11 22 1 4 8 19

The mean score of a placement exam for entrance into a math class is 80, with a standard deviation of 10. Use the Empirical Rule to find the percentage of scores that lie between 60 and 80. (Assume the data set has a bell-shaped distribution.)

95%

34%

47.5%

68%

The mean score of a competency test is 77, with a standard deviation of 4. Use the Empirical Rule to find the percentage of scores between 69 and 85. (Assume the data set has a bell-shaped distribution.)

95%

68%

50%

99.7%

The mean SAT verbal score is 478, with a standard deviation of 98. Use the Empirical Rule to determine what percent of the scores lie between 380 and 478. (Assume the data set has a bell-shaped distribution.)

34%

47.5%

68%

49.9%

The manager of a bank recorded the amount of time a random sample of customers spent waiting in line during peak business hours one Monday. The frequency distribution below summarizes the results. Approximate the sample mean. Round your answer to one decimal place.

9.0

13.5

9.2

7.7

A random sample of 30 high school students is selected. Each student is asked how many hours he or she spent on the Internet during the previous week. The results are shown in the histogram. Estimate the sample mean.

8.1

8.3

7.9

7.7

In a random sample, 10 students were asked to compute the distance they travel one way to school to the nearest tenth of a mile. The data is listed below.

a) If a constant value k is added to each value, how will the standard deviation be affected?

b) If each value is multiplied by a constant k, how will the standard deviation be affected?

1.1 5.2 3.6 5.0 4.8 1.8 2.2 5.2 1.5 0.8

154 156 165 165 170 171 172 180 184 185

189 189 190 192 195 198 198 200 200 200

205 205 211 215 220 220 225 238 255 265

Find the z-score for the value 55, when the mean is 58 and the standard deviation is 3.

z = 0.90

z = -0.90

z = -1.00

z = -1.33

The test scores of 30 students are listed below. Find P30.

31 41 45 48 52 55 56 63 65 67 67 69 70 70 74 75 78 79 79 80 81 83 85 85 87 90 92 95 99

67

56

90

63

A teacher gives a 20-point quiz to 10 students. The scores are listed below. What percentile corresponds to the score of 12?

80 8 10 7 15 16 12 19 14 9

13

12

25

40

The scores of the top ten finishers in a recent LPGA Valley of the Stars Tournament are listed below. (Source: Los Angeles Times)

71 67 67 72 73 68 72 72

Find the mode score.

67

73

72

76

The top 14 speeds, in miles per hour, for Pro-Stock drag racing over the past two decades are listed below. Find the median speed.

181.1 202.2 190.1 201.4 191.3 201.4 192.2 201.2 193.2 201.2 194.5 199.2 196.0 196.2

201.2

192.2

196.7

196.1

For the following data set, approximate the sample standard deviation of phone calls per day.

8-11 18

12-15 23

16-19 38

20-23 47

24-27 32

2.9

18.8

3.2

5.1

Find the range of the data set represented by the graph.

20

15

10

5

0 1 2 3 4 5 6 7

a) 20

b) 17

c) 6

d) 5

Find the z-score for the value 70, when the mean is 76 and the standard deviation is 2.

z= -.89

z= -3.00

z= .89

z= -3.50

The average IQ of students in a particular calculus class is 110, with a standard deviation of 5. The distribution is roughly bell-shaped. Use the Empirical Rule to find the percentage of students with an IQ above 120.

2.5%

11.15%

15.85%

13.5%

The ages of 10 grooms at their first marriage are listed below. Find the midquartile.

35.1 24.3 46.6 41.6 32.9 26.8 39.8 21.5 45.7 33.9

43.7

34.5

34.1

34.2

For the mathematics part of the SAT the mean is 514 with a standard deviation of 113, and for the mathematics part of the ACT the mean is 20.6 with a standard deviation of 5.1. Bob scores a 660 on the SAT and a 27 on the ACT. Use z-scores to determine on which test he performed better.

ACT

SAT

For the following data, approximate the mean number of phone calls per day.

8-11 31

12-15 34

16-19 28

20-23 30

24-27 6

16

15

14

26

17

For the following data, approximate the mean number of phone calls per day.

8-11 48

12-15 16

16-19 42

20-23 34

24-27 45

18

16

37

19

17

A student receives test scores of 62, 83, and 91. The student’s final exam score is 88 and homework score is 76. Each test is worth 20% of the final grade, the final exam is 25% of the final grade, and the homework grade is 15% of the final grade. What is the student’s mean score in the class?

90.6

76.6

80.6

85.6

The grade point averages for 10 students are listed below. Find the range of the data.

2.0 3.2 1.8 2.9 .9 4.0 3.3 2.9 3.6 .8

3.2

1.4

2.45

2.8

A competency test has scores with a mean of 69 and a standard deviation of 4. A histogram of the data shows that the distribution is normal. Use the Empirical Rule to find the percentage of scores between 61 and 77.

95%

68%

99.7%

50%

SAT verbal scores are normally distributed with a mean of 446 and a standard deviation of 91. Use the Empirical Rule to determine what percent of the scores lie between 355 and 446.

47.5%

34%

68%

49.9%

SAT verbal scores are normally distributed with a mean of 426 and a standard deviation of 94. Use the Empirical Rule to determine what percent of the scores lie between 332 and 426.

49.9%

34%

68%

47.5%

SAT verbal scores are normally distributed with a mean of 450 and a standard deviation of 100. Use the Empirical Rule to determine what percent of the scores lie between 250 and 550.

83.9%

68%

34%

81.5%

0.06, 10%, 1/5

0.06, 1/5, 10%

10%, 1/5, 0.06

1/5, 10%, 0.06

.1

1

0.5

0.9

If an individual is selected at random, what is the probability that he or she has a birthday in July? Ignore leap years.

31/365

1/365

12/365

364/365

The distribution of blood types for 100 Americans is listed in the table. If one donor is selected at random, find the probability of selecting a person with blood type A+ or A-.

Blood type: o+ o- A+ A- B+ B- AB+ AB-

37 6 34 6 10 2 4 1

.4

.34

.6

.45

At the local racetrack, the favorite in a race has odds 3:2 in favor of winning. What is the probability that the favorite wins the race?

0.8

0.2

0.6

0.4

Classify the events as dependent or independent. Events A and B where

P(A) = 0.8, P(B) = 0.1, and P(A and B) = 0.07

dependent

independent

A card is drawn from a standard deck of 52 playing cards. Find the probability that the card is an ace or a king.

4/13

2/13

8/13

1/13

The access code to a house’s security system consists of five digits. How many different codes are available if each digit can be repeated?

3125

5

100,000

32

Seven guests are invited for dinner. How many ways can they be seated at a dinner table if the table is straight with seats only on one side?

40,320

720

4

5040

If one card is drawn from a standard deck of 52 playing cards, what is the probability of drawing a red card?

1/2

1/13

1/52

1/4

The distribution of Master’s degrees conferred by a university is listed in the table.

Major Frequency

Mathematics 216

English 207

Engineering 86

Business 176

Education 204

What is the probability that a randomly selected student graduating with a Master’s degree has a major of Education? Round your answer to three decimal places.

0.298

0.771

0.005

0.229

A group of students were asked if they carry a credit card. The responses are listed in the table.

class cc carrier no cc

Freshman 19 41

Sophomore 40 0

If a student is selected at random, find the probability that he or she is a freshman given that the student owns a credit card. Round your answers to three decimal places.

0.322

0.678

0.190

0.317

A group of students were asked if they carry a credit card. The responses are listed in the table

class has cc no cc

freshman 11 49

sophomore 27 13

0.289

0.270

0.711

0.980

Use Bayes’ theorem to solve this problem. A storeowner purchases stereos from two companies. From Company A, 550 stereos are purchased and 1% are found to be defective. From Company B, 850 stereos are purchased and 6% are found to be defective. Given that a stereo is defective, find the probability that it came from Company A.

66/113

11/113

102/113

17/113

Decide if the events A and B are mutually exclusive or not mutually exclusive. A card is drawn from a standard deck of 52 playing cards.

A: The result is a 7.

B: The result is a jack.

mutually exclusive

not mutually exclusive

Given that P(A or B)=1/6, P(A)=1/7, and P(A and B)=1/8, find P(B)

73/168

1/16

31/168

25/168

The distribution of Master’s degrees conferred by a university is listed in the table.

(assume that a student majors in only one subject)

Major Frequency

Mathematics 230

English 206

Engineering 86

Business 176

Education 222

What is the probability that a randomly selected student with a Master’s degree majored in English or Mathematics? Round your answer to three decimal places.

0.224

0.474

0.526

0.250

If a couple has seven boys and eight girls, how many gender sequences are possible?

16

15

6435

8

A delivery route must include stops at three cities. If the route is randomly selected, find the probability that the cities will be arranged in alphabetical order. Round your answer to three decimal places.

0.03703704

0.16666667

0.33333333

0.125

The table lists the smoking habits of a group of college students.

no yes Heavy

man 135 52 5

woman 187 21 5

If a student is chosen at random, find the probability of getting someone who is a man or a non-smoker. Round your answer to three decimal places.

0.941

0.820

0.948

0.936

The distribution of Master’s degrees conferred by a university is listed in the table.

(assume that a student majors in only one subject)

Major Frequency

Mathematics 216

English 207

Engineering 85

Business 175

Education 215

What is the probability that a randomly selected student with a Master’s degree majored in Business, Education or Engineering? Round your answer to three decimal places.

0.334

0.290

0.529

0.471

How many ways can five people, A, B, C, D, and E, sit in a row at a movie theater if C must sit to the right of but not necessarily next to B?

48

20

60

24

How many ways can five people, A, B, C, D, and E, sit in a row at a movie theater if A and B must sit together?

120

48

12

24

The Environmental Protection Agency must visit nine factories for complaints of air pollution. In how many different ways can a representative visit five of these to investigate this week?

45

362,880

15,120

5

Classify the events as dependent or independent. Event A: A red candy is selected from a package with 30 colored candies and eaten. Event B: A blue candy is selected from the same package and eaten.

dependent

independent

Decide if the events A and B are mutually exclusive or not mutually exclusive, A die is rolled.

A: The result is a 3.

B: The result is an odd number.

not mutually exclusive

mutually exclusive

A group of students were asked if they carry a credit card. The responses are listed in the table.

class cc carrier no cc

Freshman 13 47

Sophomore 22 18

If a student is selected at random, find the probability that he or she owns a credit card given that the student is a sophomore. Round your answer to three decimal places.

0.550

0.450

0.220

0.629

If one card is drawn from a standard deck of 52 playing cards, what is the probability of drawing an ace?

1/2

1/4

1/52

1/13

Classify the statement as an example of classical probability, empirical probability, or subjective probability. In California’s Pick Three lottery, a person selects a 3-digit number. The probability of winning California’s Pick Three lottery is 1/1000

empirical probability

classical probability

subjective probability

A study of 1000 randomly selected flights of a major airline showed that 782 of the flights arrived on time. What is the probability of a flight arriving on time?

500/109

391/500

109/500

500/391

The events A and B are mutually exclusive. If P(A) = 0.2 and P(B) = 0.1, what is P(A and B)?

0.5

0.3

0

0.02

The table lists the smoking habits of a group of college students.

no yes Heavy

man 135 41 5

woman 187 21 5

If a student is chosen at random, find the probability of getting someone who is a man or a woman. Round your answer to three decimal places.

0.918

0.197

0.803

1

Use Bayes’ theorem to solve this problem. A storeowner purchases stereos from two companies. From Company A, 600 stereos are purchased and 11% are found to be defective. From Company B, 350 stereos are purchased and 1% are found to be defective. Given that a stereo is defective, find the probability that it came from Company A.

77/139

132/139

7/139

12/139

Find the area under the standard normal curve to the left of z = 1.5

0.1599

0.7612

0.9332

0.0668

Use the standard normal distribution to find P(0 < z < 2.25). 0.5122 0.7888 0.4878 0.8817

Find the area of the indicated region under the standard normal curve.

0.309

0.6562

1.309

0.3438

The lengths of pregnancies of humans are normally distributed with a mean of 268 days and a standard deviation of 15 days. Find the probability of a pregnancy lasting less than 250 days.

0.1151

0.0066

0.1591

0.0606

Find the z-scores for which 98% of the distribution’s area lies between -z and z.

(-0.99,0.99)

(-1.96, 1.96)

(-1.645, 1.645)

(-2.33, 2.33)

Use a standard normal table to find the z-score that corresponds to the cumulative area of 0.01.

-0.255

0.255

-2.33

2.33

Two high school students took equivalent language tests, one in German and one in French. The student taking the German test, for which the mean was 66 and the standard deviation was 8, scored an 82, while the student taking the French test, for which the mean was 27 and the standard deviation was 5, scored a 35. Compare the scores.

a)A score of 82 with a mean of 66 and a standard deviation of 8 is better.

b)The two scores are statistically the same.

c)You cannot determine which score is better from the given information.

d)A score of 35 with a mean of 27 and a standard deviation of 5 is better.

The lengths of pregnancies are normally distributed with a mean of 264 days and a standard deviation of 15 days. If 36 women are randomly selected, find the probability that they have a mean pregnancy between 264 days and 266 days.

0.5517

0.7881

0.2881

0.2119

Find the area under the standard normal curve to the right of z = -1.25.

0.7193

0.6978

0.5843

0.8944

An airline knows from experience that the distribution of the number of suitcases that get lost each week on a certain route is approximately normal with mean = 15.5 and standard deviation= 3.6. What is the probability that during a given week the airline will lose less than 20 suitcases?

0.1056

0.3944

0.8944

0.4040

Assume that the heights of men are normally distributed with a mean of 69.0 inches and a standard deviation of 2.8 inches. The U.S. Marine Corps requires that men have heights between 64 and 78 inches. Find the percentage of men meeting these height requirements.

31.12%

96.26%

99.93%

3.67%

Find the z-score for which 99% of the distribution’s area lies between -z and z.

(-1.645, 1.645)

(-2.575, 2.575)

(-1.96, 1.96)

(-1.28, 1.28)

Assume that the heights of men are normally distributed with a mean of 67.9 inches and a standard deviation of 2.8 inches. If 64 men are randomly selected, find the probability that they have a mean height greater than 68.9 inches.

0.8188

0.0021

9.9671

0.9005

Assume that blood pressure readings are normally distributed with a mean of 116 and a standard deviation of 4.8. If 36 people are randomly selected, find the probability that their mean blood pressure will be less than 118.

0.8615

0.9938

0.0062

0.8819

A coffee machine dispenses normally distributed amounts of coffee with a mean of 12 ounces and a standard deviation of 0.2 ounce. If a sample of 9 cups is selected, find the probability that the mean of the sample will be less than 12.1 ounces.

0.3216

0.0668

0.9332

0.2123

A coffee machine dispenses normally distributed amounts of coffee with a mean of 12 ounces and a standard deviation of 0.2 ounce. If a sample of 9 cups is selected, find the probability that the mean of the sample will be greater than 12.1 ounces.

0.9332

0.2123

0.0668

0.3216

Compare the scores: a score of 220 on a test with a mean of 200 and a standard deviation of 21 and a score of 90 on a test with a mean of 80 and a standard deviation of 8.

a) A score of 220 with a mean of 200 and a standard deviation of 21 is better.

b) The two scores are statistically the same.

c) A score of 90 with a mean of 80 and a standard deviation of 8 is better.

d) You cannot determine which score is better from the given information.

Find the area under the standard normal curve between z = 0 and z = 3.

0.4641

0.9987

0.0010

0.4987

0.7682

0.8944

0.1056

0.2318

Find the area under the standard normal curve to the right of z = -1.25.

0.7193

0.6978

0.5843

0.8944

Use the standard normal distribution to find P(0 < z < 2.25). 0.5122 0.7888 0.4878 0.8817

Find the area of the indicated region under the standard normal curve.

0.0968

0.0823

0.9032

0.9177

IQ test scores are normally distributed with a mean of 99 and a standard deviation of 11. An individual’s IQ score is found to be 109. Find the z-score corresponding to this value.

-1.10

0.91

-0.91

1.10

The lengths of pregnancies of humans are normally distributed with a mean of 268 days and a standard deviation of 15 days. A baby is premature if it is born three weeks early. What percentage of babies are born prematurely?

6.81%

8.08%

10.31%

9.21%

The distribution of cholesterol levels in teenage boys is approximately normal with mean= 170 and standard deviation= 30 (Source: U.S. National Center for Health Statistics). Levels above 200 warrant attention. Find the probability that a teenage boy has a cholesterol level greater than 200.

0.3419

0.1587

0.8413

0.2138

0.1056

0.8314

0.4040

0.3944

Assume that the heights of men are normally distributed with a mean of 69.0 inches and a standard deviation of 2.8 inches. The U.S. Marine Corps requires that men have heights between 64 and 78 inches. Find the percentage of men meeting these height requirements.

31.12%

96.26%

99.93%

3.67%

IQ test scores are normally distributed with a mean of 100 and a standard deviation of 15. Find the x-score that corresponds to a z-score of -1.645.

82.3

75.3

91.0

79.1

Use a standard normal table to find the z-score that corresponds to the cumulative area of 0.01.

-0.255

0.255

-2.33

2.33

A tire company finds the lifespan for one brand of its tires is normally distributed with a mean of 47,500 miles and a standard deviation of 3000 miles. If the manufacturer is willing to replace no more than 10% of the tires, what should be the approximate number of miles for a warranty?

51,340

52,435

42,565

43,660

Based on previous clients, a marriage counselor concludes that the majority of marriages that begin with cohabitation before marriage will result in divorce. Does this statement describe inferential statistics or descriptive statistics?

inferential statistics

descriptive statistics

From past figures, it is predicted that 43% of the registered voters in California will vote in the June primary. Does this statement describe:

descriptive statistics?

inferential statistics?

Classify the number of seats in a movie theater as qualitative data or quantitative data.

qualitative data

quantitative data

Identify the level of measurement for data that are a list of 1247 social security numbers.

ratio

ordinal

nominal

interval

Identify the level of measurement for data that are the numbers on the shirts of a girl’s soccer team.

ratio

ordinal

nominal

interval

What method of data collection would you use to collect data for a study where a drug was given to 57 patients and a placebo to another group of 57 patients to determine if the drug has an effect on a patient’s illness?

use sampling

use a simulation

take a census

perform an experiment

A researcher for an airline interviews all of the passengers on five randomly selected flights. What sampling technique is used?

systematic

random

convenience

stratified

cluster

At a local community college, five statistics classes are randomly selected and all of the students from each class are interviewed. What sampling technique is used?

systematic

random

convenience

stratified

cluster

Thirty-five sophomores, 35 juniors and 49 seniors are randomly selected from 230 sophomores, 280 juniors and 577 seniors at a certain high school. What sampling technique is used?

random

systematic

stratified

convenience

cluster

max: 14; min: 12

max: 54; min: 12

max: 54; min: 15

max: 17; min: 12

Use the ogive below to approximate the number in the sample.

28

100

80

341

A sample of candies have weights that vary from 2.35 grams to 4.75 grams. Use this information to find the upper and lower limits of the first class if you wish to construct a frequency distribution with 12 classes.

2.35- 2.75

2.35- 2.65

2.35- 2.54

2.35- 2.55

A city in the Pacific Northwest recorded its highest temperature at 74 degrees Fahrenheit and its lowest temperature at 23 degrees Fahrenheit for a particular year. Use this information to find the upper and lower limits of the first class if you wish to construct a frequency distribution with 10 classes.

23-27

18-28

23-28

23-29

Identify the class width used in the frequency distribution.

Miles (per day) Frequency

1 – 6 28

7 – 12 21

13 – 18 8

19 – 24 11

7

6

5

12

Identify the midpoint of the first class.

Weight (in Pounds) Frequ.

135-139 6

140-144 4

145-149 11

150-154 15

155-160 8

137

139

135

11

Identify the midpoint of the first class.

Height (in inches) Frequency

50-52 5

53-55 8

56-58 12

59-61 13

62-64 11

52

50

51

49.5

The top 14 speeds, in miles per hour, for Pro-Stock drag racing over the past two decades are listed below. Find the mode speed.

181.1 202.2 190.1 201.4 191.3 201.4 192.2 201.2 193.2 201.2 194.5 199.2 196.0 196.2

bimodal

201.2

no mode

201.4

The top 14 speeds, in miles per hour, for Pro-Stock drag racing over the past two decades are listed below. Find the median speed.

181.1 202.2 190.1 201.4 191.3 201.4 192.2 201.2 193.2 201.2 194.5 199.2 196.0 196.2

201.2

196.1

196.7

192.2

For the following data, approximate the mean number of phone calls per day.

phone calls (per day) Freque.

8-11 48

12-15 16

16-19 42

20-23 34

24-27 45

16

37

19

17

18

The heights (in inches) of 10 adult males are listed below. Find the sample standard deviation.

70 72 71 70 69 73 69 68 70 71

1.49

2.38

3

70

The grade point averages for 10 students are listed below. Find the range of the data.

2.0 3.2 1.8 2.9 .9 4.0 3.3 2.9 3.6 .8

2.8

1.4

2.45

3.2

Grade points are assigned as follows: A = 4, B = 3, C = 2, D = 1, and F = O. Grades are weighted according to credit hours. If a student receives an A in a four-unit class, a D in a two-unit class, a B in a three-unit class and a C in a three-unit class, what is the student’s grade point average?

2.75

2.50

3.00

1.75

Find the z-score for the value 88, when the mean is 95 and the standard deviation is 7.

z = -1.14

z = -1.00

z = 0.85

z = -0.85

The average IQ of students in a particular calculus class is 110, with a standard deviation of 5. The distribution is roughly bell-shaped. Use the Empirical Rule to find the percentage of students with an IQ above 120.

15.85%

2.5%

13.5%

11.15%

The cholesterol levels (in milligrams per deciliter) of 30 adults are listed below. Find Q1.

154 156 165 165 170 171 172 180 184 185 189 189 190 192 195 198 198 200 200 200 205 205 211 215 220 220 225 238 255 265

171

180

184.5

200

The birth weights for twins are normally distributed with a mean of 2353 grams and a standard deviation of 647 grams. Use z-scores to determine which birth weight could be considered unusual.

1200g

2000g

3600g

2353g

How many ways can five people, A, B, C, D, and E, sit in a row at a movie theater if A and B must sit together?

24

48

120

12

If a couple plans to have five children, how many gender sequences are possible?

5

32

25

3125

A single six-sided die is rolled. Find the probability of rolling a number less than 3.

0.25

0.333

0.5

0.1

Classify the events as dependent or independent.

The events of getting two aces when two cards are drawn from a deck of playing cards and the first card is replaced before the second card is drawn.

independent

dependent

Decide if the events A and B are mutually exclusive or not mutually exclusive. A student is selected at random.

A: The student is taking a math course.

B: The student is a business major.

not mutually exclusive

mutually exclusive

A group of students were asked if they carry a credit card. The responses are listed in the table.

has cc no cc

13 47

22 18

If a student is selected at random, find the probability that he or she owns a credit card given that the student is a sophomore. Round your answer to three decimal places.

0.629

0.450

0.550

0.220

Classify the statement as an example of classical probability, empirical probability, or subjective probability. The probability that a newborn baby is a boy is 1/2.

empirical probability

classical probability

subjective probability

A study of 1000 randomly selected flights of a major airline showed that 782 of the flights arrived on time. What is the probability of a flight arriving on time?

391/500

500/391

109/500

500/109

The events A and B are mutually exclusive. If P(A) = 0.2 and P(B) = 0.1, what is P(A and B)?

0.3

0.02

0

0.5

The distribution of Master’s degrees conferred by a university is listed in the table.

(assume that a student majors in only one subject)

major Frequency

mathematics 216

English 207

Engineering 79

Business 179

Education 226

What is the probability that a randomly selected student with a Master’s degree majored in Business, Education or Engineering? Round your answer to three decimal places.

0.532

0.282

0.468

0.337

The chances of winning the California Lottery are one chance in twenty-two million. Does this statement describe:

inferential statistics?

Descriptive statistics?

Identify the level of measurement for data that are the temperature of 90 refrigerators.

nominal

interval

ordinal

ratio

A market researcher randomly selects 200 drivers under 35 years of age and 100 drivers over 35 years of age. What sampling technique was used?

random

stratified

systematic

cluster

convenience

Classify the statement as an example of classical probability, empirical probability, or subjective probability. In California’s Pick Three lottery, a person selects a 3-digit number. The probability of winning California’s Pick Three lottery is 1/1000.

empirical probability

classical probability

subjective probability

For the following data, approximate the mean miles per day.

Miles (per day) Frequency

1-2 23

3-4 16

5-6 26

7-8 30

9-10 29

6

5

25

7

For the following data set, approximate the sample standard deviation.

Height (in inches) Frequency

50-52 5

53-55 8

56-58 12

59-61 13

62-64 11

2.57

.98

1.86

3.85

Lengths of pregnancies of humans are normally distributed with a mean of 268 days and a standard deviation of 16 days. Use the Empirical Rule to determine the percentage of women whose pregnancies are between 252 and 284 days.

50%

68%

95%

99.7%

Seven guests are invited for dinner. How many ways can they be seated at a dinner table if the table is straight with seats only on one side?

4

720

40,320

5040

A coin is tossed. Find the probability that the result is heads.

0.9

1

0.5

0.1

Decide if the events A and B are mutually exclusive or not mutually exclusive. A die is rolled.

A: The result is an odd number.

B: The result is an even number.

mutually exclusive

not mutually exclusive

A group of students were asked if they carry a credit card. The responses are listed in the table.

has cc no cc

24 36

37 3

If a student is selected at random, find the probability that he or she owns a credit card given that the student is a freshman. Round your answer to three decimal places.

0.400

0.240

0.600

0.393

If one card is drawn from a standard deck of 52 playing cards, what is the probability of drawing a red card?

1/2

1/52

1/4

1/13

If a couple has nine boys and two girls, how many gender sequences are possible?

11

55

16

8

Classify the statement as an example of classical probability, empirical probability, or subjective probability. The probability that a train will be in an accident on a specific route is 1%.

classical probability

empirical probability

subjective probability

Determine the margin of error if the grade point averages for 10 randomly selected students from a class of 125 students has a mean of = 2.7. Assume the grade point average of the 125 students has a mean of = 2.9.

0.2

2.6

-0.2

2.8

A random sample of 40 students has a test score average with a standard deviation of 11.7. Find the margin of error if c = 0.98.

1.81

1.85

4.31

0.68

A random sample of 40 students has a test score with average = 81.5 and s = 10.2. Construct the confidence interval for the (mean symbol) population mean, if c = 0.90.

(66.3, 89.1)

(78.8, 84.2)

(51.8, 92.3)

(71.8, 93.5)

Find the critical value, tc for c = 0.99 and n = 10.

2.2821

2.262

1.833

3.250

Find the value of E, the margin of error, for c = 0.90, n = 10 and s = 3.6.

2.06

2.09

0.66

1.57

For a sample of 20 IQ scores the mean score is 105.8. The standard deviation, , is 15. Determine whether a normal distribution or a t-distribution should be used or whether neither of these can be used to construct a confidence interval.

Use a t-distribution

Use a normal distribution

Neither a normal distribution nor a t-distribution can be used.

Construct a 95% confidence interval for the population mean, . Assume the population has a normal distribution. A sample of 25 randomly selected students has a mean test score of 81.5 with a standard deviation of 10.2.

(87.12, 98.32)

(77.29, 85.71)

(66.35, 69.89)

(56.12, 78.34)

A survey of 100 fatal accidents showed that 13 were alcohol related. Find a point estimate for p, the population proportion of accidents that were alcohol related.

0.87

0.149

0.13

0.115

In a survey of 2480 golfers, 15% said they were left-handed. The survey’s margin of error was 3%. Find the confidence interval for p.

84.5%

98.5%

95%

80%

A random sample of 150 students has a grade point average with a standard deviation of 0.78. Find the margin of error if c = 0.98.

0.12

0.08

0.11

0.15

A group of 49 randomly selected students has a mean age of 22.4 years with a standard deviation of 3.8. Construct a 98% confidence interval for the population mean.

(20.3, 24.5)

(21.1, 23.7)

(19.8, 25.1)

(18.8, 26.3)

In a recent study of 42 eighth graders, the mean number of hours per week that they watched television was 19.6 with a standard deviation of 5.8 hours. Find the 98% confidence interval for the population mean.

(19.1, 20.4)

(17.5, 21.7)

(18.3, 20.9)

(14.1, 23.2)

Construct a 95% confidence interval for the population mean, . Assume the population has a normal distribution. A random sample of 16 fluorescent light bulbs has a mean life of 645 hours with a standard deviation of 31 hours.

(321.7, 365.8)

(628.5, 661.5)

(531.2, 612.9)

(876.2, 981.5)

Construct a 98% confidence interval for the population mean, . Assume the population has a normal distribution. A study of 14 bowlers showed that their average score was 192 with a standard deviation of 8.

(186.3, 197.7)

(328.3, 386.9)

(115.4, 158.8)

(222.3, 256.1)

A random sample of 10 parking meters in a beach community showed the following incomes for a day. Assume the incomes are normally distributed.

3.60 4.50 2.8 6.3 2.6 5.2 6.75 4.25 8 3

Find the 95% confidence interval for the true mean.

($1.35, $2.85)

($2.11, $5.34)

($3.39, $6.01)

($4.81, $6.31)

A local bank needs information concerning the checking account balances of its customers. A random sample of 15 accounts was checked. The mean balance was $686.75 with a standard deviation of $256.20. Find a 98% confidence interval for the true mean. Assume that the account balances are normally distributed.

($513.17, $860.33)

($238.23, $326.41)

($487.31, $563.80)

($326.21, $437.90)

A survey of 250 homeless persons showed that 86 were veterans. Find a point estimate p, for the population proportion of homeless persons who are veterans.

0.34400002

0.524

0.256

0.65599998

A survey of 2650 golfers showed that 392 of them are left-handed. Find a point estimate for p, the population proportion of golfers that are left-handed.

0.129

0.174

0.852

0.148

left-tailed

right-tailed

two-tailed

The mean age of bus drivers in Chicago is 56.9 years. If a hypothesis test is performed, how should you interpret a decision that fails to reject the null hypothesis?

There is not sufficient evidence to reject the claim = 56.9.

There is sufficient evidence to support the claim = 56.9.

There is not sufficient evidence to support the claim = 56.9.

There is sufficient evidence to reject the claim = 56.9.

Given H0: p = 0.85 and α = 0.10, which level of confidence should you use to test the claim?

80%

95%

99%

90%

Find the critical value for a two-tailed test with α = 0.01 and n = 30.

±1.96

±2.575

±2.33

±1.645

2.31

1.77

3.11

0.98

Suppose you want to test the claim that μ < 65.4. Given a sample size of n = 35 and a level of significance of α = 0.01 when should you reject H0? Reject H0 if the standardized test is less than -2.575. Reject H0 if the standardized test statistic is less than -1.96. Reject H0 if the standardized test statistic is less than -1.28. Reject H0 if the standardized test statistic is less than -1.645.

0.0244

0.1003

0.0448

0.0591

Given H0: μ = 25, Ha: μ ≠ 25, and P = 0.028. Do you reject or fail to reject H0 at the 0.01 level of significance?

reject H0

fail to reject H0

not sufficient information to decide

1.890

2.001

1.991

2.132

Find the standardized test statistic t for a sample with n = 15, x = 5.4000001, s = 0.8, and α = 0.05 if H0: μ ≤ 5.0999999. Round your answer to three decimal places.

1.728

1.452

1.631

1.312

A car maker claims that its new sub-compact car gets better than 52 miles per gallon on the highway. Determine whether the hypothesis test for this is left-tailed, right-tailed, or two-tailed.

left-tailed

two-tailed

right-tailed

The mean age of bus drivers in Chicago is greater than 56.2 years. If a hypothesis test is performed, how should you interpret a decision that fails to reject the null hypothesis?

There is sufficient evidence to support the claim μ > 56.2.

There is not sufficient evidence to reject the claim μ > 56.2.

There is sufficient evidence to reject the claim μ > 56.2.

There is not sufficient evidence to support the claim μ > 56.2.

The mean IQ of statistics teachers is greater than 160. If a hypothesis test is performed, how should you interpret a decision that rejects the null hypothesis?

There is not sufficient evidence to support the claim μ > 160.

There is sufficient evidence to support the claim μ > 160.

There is not sufficient evidence to reject the claim μ > 160.

There is sufficient evidence to reject the claim μ > 160.

The mean score for all NBA games during a particular season was less than 91 points per game. If a hypothesis test is performed, how should you interpret a decision that fails to reject the null hypothesis?

There is sufficient evidence to reject the claim μ < 91. There is sufficient evidence to support the claim μ < 91. There is not sufficient evidence to reject the claim μ < 91. There is not sufficient evidence to support the claim μ < 91

-3.82

-2.16

-5.18

-4.67

0.1030

0.0211

0.0040

0.9960

Find the standardized test statistic t for a sample with n = 25, x = 21, s = 3, and α = 0.005 if Ha: μ > 20. Round your answer to three decimal places.

1.997

1.239

1.667

1.452

Determine the standardized test statistic, z, to test the claim about the population proportion p = 0.250 given n=48 and p = 0.231. Use α = 0.01.

-1.18

-0.304

-2.87

-0.23

A researcher claims that 73% of voters favor gun control. Determine whether the hypothesis test for this claim is left-tailed, right-tailed, or two-tailed.

right-tailed

left-tailed

two-tailed

An elementary school claims that the standard deviation in reading scores of its fourth grade students is less than 3.45. Determine whether the hypothesis test for this claim is left-tailed, right-tailed, or two-tailed.

right-tailed

two-tailed

left-tailed

The mean age of bus drivers in Chicago is 47.4 years. If a hypothesis test is performed, how should you interpret a decision that rejects the null hypothesis?

There is sufficient evidence to support the claim μ = 47.4.

There is not sufficient evidence to reject the claim μ = 47.4.

There is not sufficient evidence to support the claim μ = 47.4.

There is sufficient evidence to reject the claim μ = 47.4.

The mean age of bus drivers in Chicago is greater than 56.2 years. If a hypothesis test is performed, how should you interpret a decision that fails to reject the null hypothesis?

There is sufficient evidence to support the claim μ > 56.2.

There is not sufficient evidence to reject the claim μ > 56.2.

There is sufficient evidence to reject the claim μ > 56.2.

There is not sufficient evidence to support the claim μ > 56.2.

The mean score for all NBA games during a particular season was less than 91 points per game. If a hypothesis test is performed, how should you interpret a decision that fails to reject the null hypothesis?

There is sufficient evidence to reject the claim μ < 91. There is sufficient evidence to support the claim μ < 91. There is not sufficient evidence to reject the claim μ < 91. There is not sufficient evidence to support the claim μ < 91.

The mean IQ of statistics teachers is greater than 130. If a hypothesis test is performed, how should you interpret a decision that fails to reject the null hypothesis?

There is sufficient evidence to reject the claim μ > 130.

There is not sufficient evidence to support the claim μ > 130.

There is not sufficient evidence to reject the claim μ > 130.

There is sufficient evidence to support the claim μ > 130.

Given H0: μ ≤12, for which confidence interval should you reject H0?

(11.5, 12.5)

(13, 16)

(10, 13)

Given H0: p = 0.85 and α = 0.10, which level of confidence should you use to test the claim?

80%

95%

99%

90%

Find the critical value for a left-tailed test with α = 0.025 and n = 50.

-2.575

-1.96

-1.645

-2.33

Suppose you want to test the claim that μ ≠ 3.5. Given a sample size of n = 33 and a level of significance of α = 0.05 when should you reject H0 ?

Reject H0 if the standardized test statistic is greater than 2.33 or less than -2.33

Reject H0 if the standardized test statistic is greater than 2.575 or less than -2.575.

Reject H0 if the standardized test statistic is greater than 1.96 or less than -1.96.

Reject H0 if the standardized test statistic is greater than 1.645 or less than -1.645

Suppose you are using α = 0.01 to test the claim that μ ≤ 29 using a P-value. You are given the sample statistics n = 40, x = 30.8, and s = 4.3. Find the P-value.

0.1030

0.0211

0.0040

0.9960

Given H0: μ = 25, Ha: μ ≠ 25, and P = 0.028. Do you reject or fail to reject H0 at the 0.01 level of significance?

reject H0

fail to reject H0

not sufficient information to decide

Given H0: µ ≥18and P = 0.085. Do you reject or fail to reject H0 at the 0.05 level of significance?

reject H0

fail to reject H0

not sufficient information to decide

You wish to test the claim that μ > 23 at a level of significance of α = 0.05 and are given sample statistics n = 50, x = 23.3000002, and s = 1.2. Compute the value of the standardized test statistic. Round your answer to two decimal places.

3.11

0.98

2.31

1.77

You wish to test the claim that μ > 6 at a level of significance of α = 0.05 and are given sample statistics n = 50, x = 6.3, and s = 1.2. Compute the value of the standardized test statistic. Round your answer to two decimal places.

2.31

1.77

3.11

0.98

Calculate the correlation coefficient, r, for the data below.

x -9 -7 0 -3 -5 -6 -4 -2 -1 -8

y -2 0 17 9 6 2 7 11 14 0

0.990

0.819

0.792

0.881

Calculate the correlation coefficient, r, for the data below.

x:-12 -10 -3 -6 -8-9 -7 -5-4 -11

Y:14 -3 11 0 1 4 8 -2 9 10

-0.104

-0.549

-0.581

-0.132

Given a sample with r = 0.321, n = 30, and α = 0.10, determine the standardized test statistic t necessary to test the claim ρ = 0. Round answers to three decimal places.

1.793

2.561

3.198

2.354

Given a sample with r = 0.321, n = 30, and = 0.10, determine the critical values t0 necessary to test the claim Ε = 0.

± 1.311

± 0.683

± 1.701

± 2.462

Find the equation of the regression line for the given data.

x: -5 -3 4 1 -1 -2 0 2 3 -4

y: 11 6 -6 -1 3 4 1 -4 -5 8

y= -1.885x + 0.758

y= -0.758x – 1.885

y= 0.758x + 1.885

y= 1.885x – 0.758

44

55

9

56

Use the regression equation to predict the value of y for x = 3.2. Assume that the variables x and y have a significant correlation.

x: -5 -3 4 1 -1 -2 0 2 3 -4

y: 11 6 -6 -1 3 4 1 -4 -5 8

-5.274

0.541

6.790

4.311

x: -5 -3 4 1 -1 -2 0 2 3 -4

y: 11 6 -6 -2 3 4 1 -4 -5 8

0.613

0.011

0.312

0.981

Construct a 95% prediction interval for y given x = -3.5, = 2.097x – 0.552 and se = 0.976.

x: -5 -3 4 1-1 -2 0 2 3-4

Y: -10 -8 9 1 -2 -6 -1 3 6 -8

-3.187 < y < -2.154 -10.367 < y < -5.417 -4.598 < y < -1.986 -12.142 < y < -6.475

A researcher found a significant relationship between a person’s age, x1, the number of hours a person works per week, x2, and the number of accidents, y, the person has per year. The relationship can be represented by the multiple regression equation y = -3.2 + 0.012×1 + 0.23×2. Predict the number of accidents per year (to the nearest whole number) for a person whose age is 37 and who works 54 hours per week.

10

11

9

12

The data below are the temperatures on randomly chosen days during a summer class and the number of absences on those days. Calculate the correlation coefficient, r.

temp x: 74 87 93 92 90 100 77 102 82

# of absences y: 5 9 12 12 10 17 6 17 7

0.881

0.819

0.980

0.890

The data below are the ages and systolic blood pressures (measured in millimeters of mercury) of 9 randomly selected adults. Calculate the correlation coefficient, r.

Age x: 4144 48 51 54 56 60 64 68

Pressure, y: 111 115 118 126 137 140 143 145 147.

0.908

0.890

0.960

0.998

A manager wishes to determine the relationship between the number of miles (in hundreds of miles) the manager’s sales representatives travel per month and the amount of sales (in thousands of dollars) per month. Calculate the correlation coefficient, r.

Miles traveled x 5 6 13 10 11 18 6 4 14

Sales y: 41 43 88 72 75 71 58 65 130

0.561

0.791

0.632

0.717

The data below are the number of absences and the final grades of 9 randomly selected students from a statistics class. Find the equation of the regression line for the given data.

# of absences x: 0 3 6 4 9 2 15 8 5

Final grade: 98 86 80 4 82 7192 55 76 82

y= 96.14x – 2.75

y= -96.14x + 2.75

y= -2.75x + 96.14

y= -2.75x – 96.14

The data below are the temperatures on randomly chosen days during a summer class and the number of absences on those days. What is the best predicted value for y given x = 95 Assume that the variables x and y have a significant correlation.

Temp x: 72 85 91 90 88 98 75 100 80

# of absences y: 3 7 10 10 8 15 4 15 5

15

13

12

14

The data below are the number of absences and the final grades of 9 randomly selected students from a statistics class. What is the best predicted value for y given x = 7? Assume that the variables x and y have a significant correlation.

# of absences x: 0 3 6 4 9 2 15 8 5

Final Grade y: 98 86 80 82 71 92

76

78

79

77

The data below are the ages and systolic blood pressures (measured in millimeters of mercury) of 9 randomly selected adults. Find the standard error of estimate, se, given that

age x: 38 41 45 48 51 53 57 61 65

pressure y: 116 120 123 131 142 145 148 150 152

5.572

3.099

6.981

4.199

A researcher found a significant relationship between a person’s age, x1, the number of hours a person works per week, x2, and the number of accidents, y, the person has per year. The relationship can be represented by the multiple regression equation y = -3.2 + 0.012×1 + 0.23×2. Predict the number of accidents per year (to the nearest whole number) for a person whose age is 41 and who works 31 hours per week.

5

6

4

3

The data below are the final exam scores of 10 randomly selected statistics students and the number of hours they studied for the exam. Calculate the correlation coefficient r.

hrs x: 5 7 4 10 4 6 6 7 8 5

Scores y: 66 81 61 89 67 79 86 91 91 5

0.654

0.761

0.847

0.991

Calculate the correlation coefficient, r, for the data below.

x: -10 -8 -1 -4 -6 -7 -5 -3 -2 -9

y: 2 -3 -15 -10

-0.885

-0.778

-0.995

-0.671

Given a sample with r = -0.541, n = 20, and α = 0.01, determine the standardized test statistic t necessary to test the claim Ε = 0. Round answers to three decimal places.

-5.132

-3.251

-4.671

-2.729

Given a sample with r = -0.765, n = 22, and α = 0.02, determine the critical values t0 necessary to test the claim E = 0.

± 2.080

± 2.831

± 2.528

± 1.721

The data below are the final exam scores of 10 randomly selected statistics students and the number of hours they studied for the exam. Find the equation of the regression line for the given data.

hrs x: 3 5 2 8 2 4 4 5 6

Scores Y: 65 80 60 88 66 78 85 90 90 71

y= -56.11x – 5.044

y= 56.11x – 5.044

y= 5.044x + 56.11

y= -5.044x + 56.11

Use the regression equation to predict the value of y for x = 3.2. Assume that the variables x and y have a significant correlation.

x: -5 -3 4 1 -1 -2 0 2 3 -4

y: 11 6 -6 -1 3 4 1 -4 -5 8

-5.274

0.541

6.790

4.311

The data below are the temperatures on randomly chosen days during a summer class and the number of absences on those days. What is the best predicted value for y given Assume that the variables x and y have a significant correlation.

Temp x: 72 85 91 90 88 98 75 100

# of absences y: 3 7 10 10 8 15 4 15

15

13

12

14

The data below are the number of absences and the final grades of 9 randomly selected students from a statistics class. What is the best predicted value for y given Assume that the variables x and y have a significant correlation.

# of absences x: 0 3 6 4 9 2 15 8

Final grade y: 98 86 80 82 71 92 55 76

76

78

79

77

Find the standard error of estimate, se, for the data below, given that y = -2.5x

x: -1 -2 -3 -4

y: 2 6 7 10

0.532

0.349

0.675

0.866

The data below are the final exam scores of 10 randomly selected statistics students and the number of hours they studied for the exam. Find the standard error of estimate, se, given that y = 5.044x + 56.11.

hrs x: 3 5 2 8 2 4 4 5 6 3

scores y: 65 80 60 88 66 78 85 90 90 71

9.875

7.913

8.912

6.305

Construct a 95% prediction interval for y given x = -3.5, y = 2.097x – 0.552 and se = 0.976.

x: -5 -3 4 1 -1 -2 0 2 3 -4

y: -10 -8 9 1 -2 -6 -1 3 6 -8

-3.187 < y < -2.154 -10.367 < y < -5.417 -4.598 < y < -1.986 -12.142 < y < -6.475

The data below are the temperatures on randomly chosen days during a summer class and the number of absences on those days. Construct a 95% prediction interval for y, the number of days absent, given x = 95 degrees, y = 0.449x – 30.27 and se = 0.934.

tep x: 72 85 91 90 88 98 75 100 80

# of absences y: 3 7 10 10 8 15 4 15 5

4.321 < y < 6.913 3.176 < y < 5.341 9.957 < y < 14.813 6.345 < y < 8.912

A multiple regression equation is y = -35,000 + 130×1 + 20,000×2, where x1 is a person’s age, x2 is the person’s grade point average in college, and y is the person’s income. Predict the income for a person who is 26 years old and had a college grade point average of 2.3.

$485,299

$84,380

$49,380

$14,380

A researcher found a significant relationship between a person’s age, x1, the number of hours a person works per week, x2, and the number of accidents, y, the person has per year. The relationship can be represented by the multiple regression equation y = -3.2 + 0.012×1 + 0.23×2. Predict the number of accidents per year (to the nearest whole number) for a person whose age is 41 and who works 31 hours per week.

5

6

4

3

Given the size of a human’s brain, x, and their score on an IQ test, y, would you expect a positive correlation, a negative correlation, or no correlation?

no correlation

negative correlation

positive correlation