# Stats 50 multipe choice questions set 2015

You must use data provided on various worksheets of the file embedded below to answer

several questions on this exam. Worksheet names correspond to question numbers.

Use the following table for Questions 1-4.

The table below shows data for 10 pet owners who visited EmergiCare Vet Clinic.

1) The experience rating is most likely collected through:

A. Focus Group

B. Survey

C. Direct Observation

D. Experiment

2) How many variables are quantitative?

A. 1

B. 2

C. 3

D. 4

3) Experience Rating is a(n)___________variable.

A. Interval

B. Ordinal

C. Ratio

D. Nominal

4) “Breed” is measured as a(n)________variable.

A. Ordinal, since some breeds are better than others

B. Ratio, since there is no inherent zero

C. Interval, since there is inherent zero

D. Nominal, since breeds are a category

In the Excel file embedded on page 2, use the Worksheet Q5-8 to answer Questions 5-8.

5) Using the 2k > n rule, how many classes would be needed for a frequency distribution of

visual weld defects?

A. 4

B. 5

C. 6

D. 7

6) The independent variable is

A. Time, it is not affected by changes in the other variable

B. Not time, but a specific type of scatter plot in which the data points in the scatter plot are

connected with a line

C. Visual weld defects shown as a variable in the scatter plot that is influenced by changes in

the other variable

D. A visual picture of the relationship between two data points that are paired together on a

graph with a horizontal and vertical axis

7) Which Stem and Leaf plot depicts the visual weld defects?

2

3

8) Which Scatter plot depicts the visual welding defects?

4

9) Given Pareto chart directly below, on which two errors should management focus their

efforts?

A.

B.

C.

D.

Long delays directly lead to delivery errors

Delivery errors and long delays

Employee input errors and shipping delay errors

Pareto chart gives no insight

10) The Pareto chart above is a

A. a bar chart that groups several values side by side within the same category in a horizontal

direction

B. a bar chart that shows in a decreasing order the frequency of the categories that cause

quality control problems

C. a variable in the scatter plot that is influenced by changes in the other variable

D. none of the above

In the Excel file embedded on page 2, use the Worksheet Q11-14 for Questions 11-14.

The worksheet shows sales data from a local cell phone store detailing the number of cell phones

sold for the month of September. This data is a sample of their overall sales.

11) What is the mean number of cell phones sold during the month?

A. 37.41

B. 35.50

C. 36.17

D. 36.00

12) Use the method shown in our book to compute and report the median number of sales during

the month of September?

A. 35.0

B. 35.5

C. 36.0

D. 36.5

13) Use the book’s method to report the number of sales corresponding to the 45th percentile?

5

A.

B.

C.

D.

32.0

33.0

34.0

35.0

14) What is the variance of sales?

A. 14.02

B. 196.48

C. 212.72

D. 203.25

In the Excel file embedded on page 2, use the Worksheet Q15 for Question 15.

The data is from a small store that recently began offering a new and one-of-a-kind product. The

numbers relate to the first 15 days of sales, and include all sales data to date for this item.

15) What is the standard deviation of the sales of this new item?

A. 3.97

B. 12.81

C. 3.58

D. 4.62

16) Product A has sold a mean of 27 items each day with a standard deviation of 5.4. Product B

has sold a mean of 35 items with a standard deviation of 6.5. Which product has been more

consistent in sales?

A. Sales of Product A has been more consistent

B. Sales of Product B has been more consistent

C. Sales of both products are equally consistent

D. Cannot be determined

17) A data set of unknown distribution has a mean of 60 and a standard deviation of 7. At least

how much of the data lies between 46 and 74?

A. 95%

B. 99.7%

C. 68%

D. 75%

Use the following table for Questions 18 and 19. It is a sample of radar-indicated speed of

automobiles on a particular section of a highway.

Speed

45-49

50-54

55-59

60-64

65-69

70-74

Frequen

cy

2

5

7

11

15

5

18) What is the mean speed of the automobiles?

6

A.

B.

C.

D.

63.6

59.5

62.2

65.0

19) What is the standard deviation of the speed of these automobiles?

A. 6.66

B. 44.40

C. 6.22

D. 6.74

For Questions 20 – 26, use the following information. Use 4 decimals in your calculations.

As part of an IT survey, both staff and managers were asked to indicate what business and

technical skills are critical to their jobs. In total, 12 skills were included in the survey. One of the

12 skills was “Analyzing Data”. The following table reports findings about that skill:

Professional Position

Analyzing Data

Staff

Management

Total

Critical

4,374

3,633

8,007

Not critical

3,436

2,631

6,067

Total

7,810

6,264

14,074

20) What is the probability that a person selected at random is a manager?

A. 0.4451

B. 0.2581

C. 0.6329

D. 0.5549

21) What is the probability that a randomly selected person says Analyzing Data is critical skill?

A. 0.6221

B. 0.2441

C. 0.4451

D. 0.5689

22) What is the probability a randomly selected person is a manager and believes Analyzing Data

is a critical skill?

A. 0.4537

B. 0.2581

C. 0.5800

D. 0.4451

23) What is the probability that a randomly selected person is a manager or believes Analyzing

Data is a critical skill?

A. 0.4451

B. 0.2581

C. 0.7559

D. 0.2441

24) Given that a person is a manager, what is the probability that he/she believes Analyzing Data

is a critical skill?

7

A.

B.

C.

D.

0.2581

0.4537

0.5800

0.7263

25) The respondents were asked to consider the 12 skills included in the study and pick 4 which

they thought are critical to their job. How many different ways are possible for an individual

to make his/her selection?

A. 48

B. 495

C. 20,736

D. 11,880

26) The respondents were asked to consider the 12 skills included in the study, and rank (as 1, 2,

3, and 4) their top 4 choices. How many different ways are there that a person could make

his/her selection?

A. 48

B. 495

C. 20,736

D. 11,880

For Questions 27 – 29, use the following information. Carry out calculations to 4 decimals.

Laid-off workers who become entrepreneurs because they cannot find meaningful employment

with another company are known as entrepreneurs by necessity. The Wall Street Journal reported

that these entrepreneurs by necessity are less likely to grow into large businesses than are

entrepreneurs by choice. The article states that 89% of the entrepreneurs in the United States are

entrepreneurs by choice and 11% are entrepreneurs by necessity. Only 2% of entrepreneurs by

necessity expect their new business to employ 20 or more people within 5 years. But, 14% of

entrepreneurs by choice expect to employ at least 20 people within 5 years.

27) What is the probability that a randomly selected entrepreneur believes his/her business will

grow to employ at least 20 people in 5 years?

A. 0.1268

B. 0.1246

C. 0.0174

D. 0.1078

28) What is the probability that a randomly selected individual is an entrepreneur by necessity

and expects his/her business will grow to employ at least 20 people in 5 years?

A. 0.0200

B. 0.0022

C. 0.1400

D. 0.8765

29) An entrepreneur is selected at random who expects his/her new business will employ 20 or

more people within 5 years. What is the probability that this individual is an entrepreneur by

choice?

8

A.

B.

C.

D.

0.1400

0.1246

0.9826

0.1268

30) A state motor vehicle department would like to know how many license plate numbers are

available if a license plate number consists of three letters (capital letters only) followed by

three numbers (0 through 9). The answer is:

A. 18,940

B. 28,497

C. 17,576,000

D. 18,920,020

Use the following table and information to answer Questions 31 – 33. The table shows

discrete probability distribution for the number of errors per a page of a medieval text.

31) What is the value of c (hint: the sum of probabilities equals 1.00)?

A. Exactly equal to zero

B. Less than 1

C. Greater than 1

D. Cannot be computed since there are too many variables

32) What is the mean of the discrete probability distribution

A. Exactly equal to zero

B. Less than 1

C. Greater than 1

D. Cannot be computed since there are too many variables

33) What is the variance of the discrete probability distribution (to four decimal places)?

A. 1.1947

B. 1.4275

C. 7.6345

D. 9.3428

34) The 3-year-survival rate for a certain group of cancer patients is known to be 0.60. What is

the probability (to four decimal places) that in a group of 10 patients, more than 5 patients

survive at least 3 years (note: 3-year-survival is a binary outcome, and “success” is defined as

survival).

A. .0011

B. .2006

C. .2508

D. .6331

35) Customers arrive at a bank teller’s booth at a rate of 2 per minute. What is the probability (to

four decimal places) that 4 customers will arrive at the bank teller’s booth within the next

minute (assume a Poisson distribution)?

A. .0902

9

B. .3324

C. .6723

D. 1.143

36) Leaks occur along a pipeline at the mean rate of 0.5 leaks per mile. Assume Poisson

properties apply. What is the probability that a 3 mile stretch will have no leaks? (to four

decimal places)

A. 0.0498

B. 0.6065

C. 0.3679

D. 0.2231

37) An insurance company has a call center that makes cold calls to individuals trying to sell life

insurance. The probability of making a sale is 0.10. Assume binomial properties apply. If an

individual in the center makes 20 calls, what is the probability they will make sales on more

than 4 calls?

A. 0.9569

B. 0.0431

C. 0.2000

D. 0.0898

38) A student has not been to class and must pass a 20 question true/false exam to continue in the

course. The student will guess on every question and must get at least 14 correct to pass the

test. What is the probability that the student will pass the test?

A. 0.0577

B. 0.0739

C. 0.0370

D. 0.5000

39) Customers arrive at a bakery at an average rate of 10 customers per hour. What is the

probability that less than 5 customers will arrive in the next hour? Assume Poisson arrivals.

A. 0.0378

B. 0.0293

C. 0.2500

D. 0.1126

40) Customers arrive at a bakery at an average rate of 10 customers per hour. What is the

probability that exactly 20 customers will arrive in the next 2 hours? Arrivals are Poisson.

A. 0.0019

B. 0.1251

C. 0.0888

D. 0.5591

For Questions 41 – 44, use Excel and the following information. According to

botttledwater.org, in 2012, the per capita consumption of bottled water in the USA was reported

as 30.8 gallons. Assume the per capita consumption of bottled water in the USA is normally

distributed with mean equal to 30.8 gallons and standard deviation equal to 10 gallons.

10

41) What is the probability that someone in the United States consumed more than 32 gallons of

bottled water in 2012?

A. 0.1294

B. 0.4522

C. 0.8268

D. 0.5478

42) What is the probability that someone in the United States consumed between 10 and 20

gallons of bottled water in 2012?

A. 0.1213

B. 0.0188

C. 0.0177

D. 0.2343

43) What is the probability that someone in the United States consumed less than10 gallons of

bottled water in 2012?

A. 0.1213

B. 0.0188

C. 0.0177

D. 0.0188

44) Ninety nine percent (99%) of the people in the United States consumed less than how many

gallons of bottled water? Round off to one decimal

A. 7.5

B. 20.8

C. 54.1

D. 68.3

For Questions 45 – 47, use the following information. Downloading times at a website is

assumed to be uniformly distributed between 4.5 to 9.5 seconds.

45) What is the probability that download time will take 9 to 13 seconds?

A. 0.05

B. 0.23

C. 0.10

D. 0.5

46) What is the probability that download time takes between 5 to 9 seconds?

A. 0.6

B. 0.8

C. 0.43

D. 0.8

47) What is the mean and standard deviation for download time?

A. 7 and 1.44

B. 2 and 2.35

C. 9 and 1.47

D. 5 and 3.07

11

Use the following information to answer Questions 48 – 50.

The time between unplanned shutdowns of a power plant has an exponential distribution with a

mean of 20 days.

48) Find the probability that the time between two unplanned shutdowns is less than 14 days

A. 0.3347

B. 0.1295

C. 0.5034

D. 0.7864

49) Find the probability that the time between two unplanned shutdowns is more than 21 days

A. 0.2947

B. 0.65

C. 0.5

D. 0.3499

50) Find the probability that the time between two unplanned shutdowns is between 7 to 9 days

A. 0.0588

B. 0.9210

C. 0.0671

D. 0.1017