
1. (10 points) True or False. Justify your answers for full credit.

(a) If the variance from a data set is zero, then all observations must be zero in this data set.

(b) The variance of a data set cannot be negative, but the standard deviation can be negative.

(c) Suppose the minimum for a data set is 0.12. A careless assistant records it as 1.2, which is the

only mistake in the record keeping. The mistake will increase the mean as well as the median of

the data set

(d) The following distribution has a positive skew.

(e) Quarterfinal range can measure central tendency.

(For Questions 2 to 8) Choose the correct answer. Justify your answers for full credit. (2 points

each)

2. An agency conducts a survey on the choice of vegetable by Americans. It is reported by the

agency that 57% of the respondents prefers broccoli. The value 57% is

a. a parameter,

b. a statistic,

c. neither of the above.

3. The volume of water in a glass is 12 oz. The value of 12 is from

a. a continuous data set,

b. a discrete data set,

c. neither of the above.

4. Which of the following is a qualitative variable?

a. Weight in kilograms

b. Number of days without precipitation

Page 2 of 6

c. Ethnicity

d. Average daily temperature

5. For the following stem and leaf plot, how many numbers are there between 3 and 4? Please

note the numbers in the stem are in ones.

433

356

200456

100134

01245589

00679

1005559

27

a. 0

b. 2

c. 11

d. 56

6. Identify the scale of measurement for the following military hierarchy: Lieutenant, Captain,

Major

a. Interval

b. Nominal

c. Ratio

d. Ordinal

7. In a histogram, frequencies are represented by_______

a. Lines

b. Bars

c. portions of the pie

d. leaves

Page 3 of 6
8. For the following histogram of test scores, The majority of scores came between______
(a) 39.5 and 49.5
(b) 89.5 and 99.5
(c) 79.5 and 89.5
(d) 159.5 and 169.5
(For Questions 9 & 10) The checkout times (in minutes) for 10 randomly selected customers at a
large supermarket during the store’s busiest time are as follows:
6 5 8 12 8
13 10 14 7 11
9. (5 points) (Show work) Find the minimum, maximum, median, mode and mean of the
checkout time. (Round the answers to one decimal place)
Page 4 of 6
10. (5 points) (Show work) Prepare a frequency distribution with a class width of 2 minutes by
completing the following table.
Checkout Time Frequency Relative Frequency
5.0 – 6.9
7.0 – 8.9
9.0 – 10.9
11.0 – 12.9
13.0 – 14.9
__________________________________________________________________
(For Questions 11 & 12) To qualify for a mortgage, an applicant needs to have a good FOCI
credit score. We chose a random sample of 5 applicants from a local bank, and their FOCI scores
are 760, 650, 820, 540 and 620.
11. (4 points) (Show work) What is the standard deviation of the FOCI scores in the
sample? Please show your intermediate calculation in the following table; you may not need all
columns based on the formula you use. (Round the answer to two decimal places)
FOCI
Score x x
2
xmean (xmean)
2
760
650
820
540
620
Page 5 of 6
Sum
12. (2 points) (Show work) A data value is considered unusual if it’s above or below 2 standard
deviations from the mean. Are any of these FOCI scores considered unusual? Explain.