CRJ 310 Statistics in Criminal JusticeExam #1 (Part I + Part II = 75 Total Points)
Name
Part II: Take-Home Exam (30 Points) Due on Friday, September 27 in class
Directions: Please write your answers directly on the exam sheets (a total of 3 pages). Note that
this is an exam and it must be completed independently without any assistance. You are
prohibited from a discussion with anyone else, including students in our class. If two or
more students answer take-home exam questions in a similar way, they will be treated as
violating exam rules as well as academic honesty and integrity, and they will not receive
any point for both parts of the exam. It is my discretion to determine whether the take-
home exams completed by two or more students are similar. Notes and texts are allowed for
the exam, however. Failure to abide by exam rules is considered cheating and will result in a
lower grade or a loss of all points. Upon completion, please turn in the take-home part of the
exam in class on the due date. Turning it in later will not be accepted.
C. Problems. Solve the following problems. Please show all work (i.e., calculations and results)
as partial credit will be given for all questions. Fail to show the process or calculation will get no
more than half of credit. Please also round your answers to ONE decimal place (e.g., 30.7).
The hourly wages of seven clerks in a U.S. company and seven clerks in a CANADAIAN
company are as follows:
6 12 7 14 12 11 8
U.S. company:
(in U.S. dollars)
16
15
13
10
11
13
Canadian company: 13
(in CANADIAN dollars)
Please answer the following questions based on information from the above table.
1. (1 point) Indicate the level of measurement (i.e., nominal, ordinal
, interval, or ratio) for the
hourly wages of clerks in the two companies. Please provide the reason for your choice.
2. (2.5 points) Identify the formula and calculate the range of hourly wages for EACH company.
-range
3. (3 points) Identify the formula used to calculate percentages. With the two companies
COMBINED, calculate the percentage of clerks earning hourly wages over $9 U.S. dollars AND
over $14 CANADIAN dollars. Note: The final answer has only one percentage.
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4. (6 points) Find the mode, median, and mean for the clerkshourly wages paid by the
CANADIAN company. You need a calculation or explanation of how you get the answer.
-mode
-median
-mean
5. (4 points) Regarding the U.S. clerks’ hourly wages, the mode, median, and mean are $12, 811,
and $10 U.S. dollars, respectively. (a) Based on the information, how does the distributions of
the U.S. data look like in terms of skewness (e.g., symmetrical, positively skewed, or negatively
skewed)? (b) If you find positive or negative skews, please also indicate the seriousness of
skewness. Please explain how you determine whether there is skewness for the distribution of the
variable.
6. (1.5 points) Which measure of central tendency would be the best for the distribution of the
U.S. data, based on the information in Question 5? Please explain your choice(s).
7.(1.5 points) Which measure(s) appropriately represent typicality of the CANADIAN data,
based on the answers you have obtained from Question 4? Please explain your choice(s).
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8. (5 points) Identify the formula and calculate the variance and standard deviation for the
clerks’ hourly wages paid by the U.S. company (mean = 10). Note that your answers for both the
variance and standard deviation should be between 1.0 and 10.0. If your answers are not within
this range, they must be incorrect, and you should re-do all calculations.
—variance
-standard deviation
9. (1.5 points) In the current example, you are unable to make a direct comparison of variability
in hourly wages between the two companies based solely on the standard deviation you have
found from Question 8 for the U.S. company as well as the standard deviation of 1.93 from the
CANADIAN company. Why?
10. (4 points) To tackle the problem in Question 9, the coefficient of relative variation (CRV)
has served as one good approach to determining which company has greater variability in its
employees’ hourly wages. Identify the formula for CRV, compute CRVs for BOTH companies,
and then determine which company has greater variability in its employees’ hourly wages.
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