Statistics Midterm Exam

Name___________________________________

Determine whether the numerical value is a parameter or a statistic. Explain your reasoning.

1) (3 pts) The average salary of all assembly-line employees at a certain car manufacturer is

$44,000.

A) Parameter

B) Statistic

Identify whether the statement describes inferential statistics or descriptive statistics.

2) (3 pts) The chances of winning the California Lottery are one chance in twenty-two million.

A) inferential statistics

B) descriptive statistics

Determine whether the data are qualitative or quantitative.

3) (3 pts) The number of complaint letters received by the United States Postal Service in a given

day

A) qualitative

B) quantitative

Identify the data set’s level of measurement.

4) (3 pts) The amounts of fat (in grams) in 37 cookies

A) interval

B) ratio

1)

2)

3)

4)

C) ordinal

5) (3 pts) numbers on the shirts of a girl’s soccer team

A) ratio

B) nominal

D) nominal

5)

C) ordinal

D) interval

Determine whether the study is an observational study or an experiment.

6) (3 pts) The personnel director at a large company would like to determine whether the company

cafeteria is widely used by employees. She calls each employee and asks them whether they

usually bring their own lunch, eat at the company cafeteria, or go out for lunch.

A) observational study

B) experiment

Identify the sampling technique used.

7) (3 pts) A community college student interviews everyone in a particular statistics class to

determine the percentage of students that own a car.

A) systematic

B) random

C) cluster

D) convenience

E) stratified

8) (3 pts) A researcher randomly selected 70 of the nation’s middle schools and interviewed all of

the teachers at each school.

A) systematic

B) random

C) convenience

D) stratified

E) cluster

1

6)

7)

8)

9) (3 pts) 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 not replaced before the

second card is drawn.

A) dependent

B) independent

9)

10) (3 pts) 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

10)

A) classical probability

B) subjective probability

C) empirical probability

11) (3 pts) Decide if the events A and B are mutually exclusive or not mutually exclusive. A person is

selected at random.

A: Their birthday is in the fall.

B: Their birthday is in October.

A) not mutually exclusive

B) mutually exclusive

11)

12) (3 pts) State whether the variable is discrete or continuous.

The number of goals scored in a soccer game

A) discrete

B) continuous

12)

Determine the number of outcomes in the event. Then decide whether the event is a simple event or not. Explain your

reasoning.

13) (3 pts) You randomly select a computer from a batch of 50 which contains 3 defective computers. 13)

Event B is selecting a defective computer.

A) 3; Simple event because it is an event that consists of only one type of computer.

B) 3; Not a simple event because it is an event that consists of more than a single outcome.

C) 50; Not a simple event because it is an event that consists of more than a single outcome.

D) 1; Simple event because it is an event that consists of only one type of computer.

Provide an appropriate response.

14) (3 pts) Determine whether the approximate shape of the distribution in the histogram is

symmetric, uniform, skewed left, skewed right, or none of these.

A) skewed left

B) symmetric

C) skewed right

2

D) uniform

14)

15) (3 pts) Decide whether the experiment is a binomial experiment. If it is not, explain why.

Surveying 600 prisoners to see how many crimes in which they were convicted. The random

variable represents the number of crimes in which each prisoner was convicted.

A) Not a binomial experiment

B) Binomial experiment

16) (5 pts) The numbers of runs batted in that Sammy Sosa hit in the first 15 years of his

major league baseball career are listed below. Find the mean, median, and mode for the

number of runs batted in. Round the mean to the nearest whole number.

13

119

70

158

33

141

25

138

93

160

70

108

119

103

16)

100

17) (5 pts) Make a box and whisker plot for the data. Use the data to identify any outliers.

17)

15 18 18 19 22 23 24

24 24 24 25 26 26 27

28 28 30 32 33 40 42

The heights (in inches) of 30 adult males are listed below.

70

67

69

72

71

71

71

70

68

70

74

67

69

69

73

73

68

74

69

71

70

68

71

71

70

71

69

71

72

68

18) (5 pts) Construct a frequency distribution, a relative frequency distribution, and a

cumulative frequency distribution using five classes.

18)

19) (5 pts) Grade points are assigned as follows: A = 4, B = 3, C = 2, D = 1, and F = 0. Grades

are weighted according to credit hours. If a student receives an A in a four-credit class, a

D in a two-credit class, a B in a three-credit class and a C in a three-credit class, what is

the student’s grade point average?

19)

Use the fundamental counting principle to solve the problem.

20) (5 pts) How many license plates can be made consisting of 3 letters followed by 3 digits?

20)

21) (5 pts) A multiple-choice test has five questions, each with five choices for the answer.

Only one of the choices is correct. You randomly guess the answer to each question.

What is the probability that you answer the first two questions correctly?

21)

22) (5 pts) Eight 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?

22)

23) (5 pts) Determine the probability distribution’s missing value.

The probability that a tutor sees 0, 1, 2, 3, or 4 students on a given day.

23)

x

0

1

2

3

4

P(x) ? 0.15 0.20 0.20 0.25

3

15)

24) (5 pts) The distribution of Master’s degrees conferred by a university is listed in the

table.

24)

Major

Frequency

Mathematics

216

English

207

Engineering

86

Business

176

Education

291

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.

25) (5 pts) A group of students were asked if they carry a credit card. The responses are

listed in the table.

Class

Freshman

Sophomore

Total

25)

Credit Card Not a Credit Card

Carrier

Carrier

Total

14

46

60

18

22

40

32

68

100

If a student is selected at random, find the probability that he or she is a sophomore

given that the student owns a credit card. Round your answers to three decimal places.

26) (5 pts) The table lists the smoking habits of a group of college students.

26)

Sex

Non-smoker Regular Smoker Heavy Smoker Total

Man

135

38

5

178

Woman

187

21

7

215

Total

322

59

12

393

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.

27) (5 pts) A test consists of 10 multiple choice questions, each with five possible answers,

one of which is correct. To pass the test a student must get 60% or better on the test. If a

student randomly guesses, what is the probability that the student will pass the test?

Use binmial distribution.

27)

28) (5 pts) A statistics professor finds that when he schedules an office hour at the 10:30 a.m.

time slot, an average of three students arrives. Use the Poisson distribution to find the

probability that in a randomly selected office hour no students will arrive.

28)

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