PRE-COURSE TEST
Student’s personal information:
Full name
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Student’s ID
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Class
:
Date of Quiz
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<Each question answered correctly earn 5 marks, The test has 20 questions in total>
<You are recommended to use NO materials (except for the calculator) during the test, answering
questions exclusively based on what you have known so far. If you do not know the answer, dont
make a guess and dont worry, and just leave the question unanswered>
Note: OQ = Open Question; T/F = True or False; T/F&B.E. = True or false, and Brief Explanation
MC = Multifple Choice questions
Q1. [OQ] What are the differences between cross-sectional data, time-series data, and panel data?
Q2. [T/F] A population is a set of existing units.
Q3. [T/F] Statistical inference is the science of using a sample of measurments to make
generalizations about the important aspects of a population of measurements.
Q4. [T/F & B.E.] For an investigation on the impact of the working-from-home policy on the
employee’s performance of a particular firm, the dataset will be a panel data. True/False? & Brief
explanation.
Q5. [OQ] For 120 respondents on a question about the customer’s satisfaction on the new product
of the firm, how many classes (categories) should we design to build a frequency histogram?
Q6. [OQ] Define scales of measurement (nominal or ordinal) for each of following variable
Qualitative Variable
Categories
1.Statistics course letter grade
A
B
C
D
E
F
2.Door choice on game show “Hay Chon Gia Dung” Door #1
Door#2
Door #3
3. Gold types (quality)
10K
14K
18K
24K
4. Restaurant ratings
*
**
***
****
*****
5. Gender
Male
Female
Q7. [MC] The following presentation of data is:
A. the frequency histogram
C. Frequency polygon
B. Scatter Plot
D. Stem & leaf
Q8. [OQ] The following data consist of the revenue growth rates (in percent) for a group of 20
firms. Construct a stem-and-leaf display for these data, given stem of 10 units and leaf of 1 unit.
36
59
42
65
91
32
56
28
49
51
30
55
33
63
70
44
42
83
53
43
Q9. [OQ] From the data given in Q8, construct a frequency distribution for the data.
Q10. [OQ] Given the information of stock funds as following, What are the unweighted mean &
weighted mean of ROR?
Stock Fund
AUM (USD)
Percentage Return (ROR)
1
150.000
6.02%
2
200.000
7.15%
3
100.000
-1.04%
Q11. [OQ] In order to control costs, a company wishes to study the amount of money its sales
force spends entertaining clients. The following is a random sample of six entertainment expenses
(dinner costs for four people) from expense reports submitted by members of the sales force.
$157 $132 $109 $145 $125 $139
Calculate mean, standard deviation (std), and variance for the expense data.
Q12. [OQ] From the answer of Q11, If a member of the sales force submits an entertainment
expense (dinner cost for four) of $190, should this expense be considered unusually high (and
possibly worthy of investigation by the company)? Explain your answer, given that the firm could
only tolerate the expense that deviates +/- 3 std(s) from the mean.
Q13. [MC] a company collected the ages from a random sample of its middle managers, with the
resulting frequency shown below.
Class Interval
Frequency
What would be the approximat shape of the
relative frequency histogram?
20 to < 25
8
A. Symmetrical
25 to < 30
6
B. Uniform
30 to <35
5
C. Multile peaks
35 to < 40
12
D. Skewed to the left
40 to < 45
15
E. Skewed to the right
45 to < 50
7
Q14. 1048 customers were randomly selected from those who had recently bought a book over
the Internet. The chart below shows the breakdown of the classification of the book type.
What percentage of the
books purchased were
either self-help or
science fiction/fantasy?
A)
18.61
B)
36.50
C)
17.88
D)
24.33
E)
22.99
Q15. [OQ] A manager’ d like to evaluate the effectiveness of advertisement that his firm is recently
running. To do so, he looks at how much each customer pays for their transactions on his firm’s
product after the advertisement campaign is launched, and he has 1250 receipts to look through.
Draw the frequency histogram & Construct an ogive graph.
What is the meaning of the value on 4th value on the cumulative frequency column
Transaction Amount ($)
0.01 – 20.00
20.01 – 40.00
40.01 – 60.00
60.01 – 80.00
80.01 – 100.00
> 100.01
Frequency
96
145
478
320
121
90
Cumulative Frequency
Q16. [OQ] From the answers in Q15, which graph is more efficient/easier for the manager in
making decision on the effectiveness of the ad campaign ? and why?
Q17. [MC] A Type I error occurs when:
A. We reject the null hypothesis H0 when the null hypothesis is true
B. We reject the alternative hypothesis H1 when the null hypothesis is true
C. We reject the alternative hypothesis H1 when the H1 is true
D. We do not reject the null hypothesis H0 when the null hypothesis is false
Q18. [MC] A Type II error occurs when:
A. We reject the null hypothesis H0 when the null hypothesis is true
B. We reject the alternative hypothesis H1 when the null hypothesis is true
C. We reject the alternative hypothesis H1 when the H1 is true
D. We do not reject the null hypothesis H0 when the null hypothesis is false
Q19. [OQ] Given the hypothesis testing at a bottling firm as follows:
H0:  = 16 oz.(~28gr) the bottling process hits the target fill – no adjustment needed.
Ha:  ≠ 16 oz. the bottling process is underfilling or overfilling the bottles and the filler
requires adjustment.
What is Type I error in this case? What are expected consequences for the firm if wrong conclusion
is made?
(optional) What is Type II error? And expected consequences when the firm manager uses your
conclusion to make business decision?
Q20. A real estate company is analyzing the selling prices of residential homes in a given
community. 140 homes that have been sold in the past month are randomly selected and their
selling prices are recorded. The statistician working on the project has stated that in order to
perform various statistical tests, the data must be distributed according to a normal distribution.
In order to determine whether the selling prices of homes included in the random sample are
normally distributed, the statistician divides the data into 6 classes of equal size and records the
number of observations in each class. She then performs a chi-square goodness-of-fit test for
normal distribution. The results are summarized in the following table.
At a significance level of .05, what is the appropriate rejection point condition?
F)
G)
H)
I)
J)
Reject H0 if χ2 > 12.5916
Reject H0 if χ2 > 11.0705
Reject H0 if χ2 > 9.3484
Reject H0 if χ2 > 7.81473
Reject H0 if χ2 > 9.48773
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