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Mid Term 2020 - Statistics for Business | Trường Đại học Quốc tế, Đại học Quốc gia Thành phố HCM

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Mid Term 2020 - Statistics for Business | Trường Đại học Quốc tế, Đại học Quốc gia Thành phố HCM

26 13 lượt tải Tải xuống

THE INTERNATIONAL UNIVERSITY– VIETNAM NATIONAL UNIVERSITY – HCMC

SCHOOL OF BUSINESS

MID-TERM EXAMINATION

Date:

Duration: 90 minutes

Student ID: .................................. Name:................................................

SUBJECT: Statistic for Business

Dean of School

Signature:

Lecturers

Signature:

Dr. Le Van Chon

Dr. Nguyen Ba Trung

Mr. Nguyen Hoang Phu

GENERAL INSTRUCTION(S)

1. Students can bring only 1 note A4 (2-sides, handwriting) and calculator

2. Other electronic decides are strictly prohibited

3. No Discussion and sharing Materials.

PLEASE ANSWER DIRECTLY ON THIS SHEET

Please round the result to 4 decimals place, e.x 0.0001

Question 1: (25 pts)

To estimate which presidential candidate will be selected in the upcoming U.S election, BBC

news has conducted a survey of U.S voters. BBC has selected randomly 3 states in the U.S,

including: New York, Washington DC, and Montana. For each selected state, BBC has phoned

randomly 1000 voters about the following information: their age, their income (measured as: less

than $5.000 per month, from $5.000 - $10.000 per month, and above $10.000 per month), their

job, and who they plan to vote for in the upcoming presidential election.

a. What is the population in this study? What is the sample in this study? (5pts)

.............................................................................................................................................................

b. What is the sampling method used in this study? (5pts)

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c. What is the variables in this study? What type of the data is each variable (Quantitative or

Categorical) (5pts)?

.............................................................................................................................................................

d.What is each variable’ level of measurement? (5pts)

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e. Is there the BBC study primarily an example of inferential or descriptive statistics? Why? (5pts)

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Question 2 (15pts)

The figure 1 below presents the relationship between wage (million VND per month) and

education (years of schooling) of 20 workers.

Figure 1. The relationship between wage and education

a. Comment on the relationship between wage and education in Figure 1? If compute the

correlation between wage and education, what is the sign of the correlation coefficient (positive

or negative)? (5pts).

............................................................................................................................................................

b. Using the above data, a researcher estimates a linear equation describing relationship between

wage and education as follows: Wage = 5.21 + 0.74*Education. Let a = 5.21, and b = 0.74,

Explain the meaning of a and b? (5pts)

............................................................................................................................................................

c. Suppose that worker A has 10 years of schooling while worker B has 5 years of schooling. What

is the predicted difference in monthly wage between A and B? (5pts)

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Question 3 (35 points)

Suppose that you are a research assistant at a market research company , you study about have a

data set as below:

15 23 15 45 78 89 18 21 42 15 65 120

a. Calculate GeoMean; Mean, Median ; Mode; midrange

b. Calculate the sample standard deviation

c. Estimate the value of the 62% percentile

d. Calculate Interquartile range

e. According to Chebyshev’s Theorem, determine the interval that at least 75% number of

population data belongs to ?

f. Suppose the dataset is a population, is the observation with its value of “120” an outlier point ?

............................................................................................................................................................

Question 4: (5 pts)

Suppose a certain country has an experiment to test a Covid-19 vaccine with two groups : 70%

of participants received the vaccine (in the Group A ) and 30% of that did not receive the

vaccine (in the Group B) . After a test, for the Group A & B , the probability of “a negative

result” is 90% and 60% in respectively. If a person gets “ a negative result” , what is a

probability that she/he came from the Group A ? (5)

............................................................................................................................................................

Question 5 : (20 pts)

The U.S. Department of Transportation reported that during November, 83.4% of Southwest

Airlines’ flights, 75.1% of US Airways’ flights, and 70.1% of JetBlue’s flights arrived on time

(USA Today, January 4, 2007). Assume that this on-time performance is applicable for flights

arriving at concourse A of the Rochester International Airport, and that 40% of the arrivals at

concourse A are Southwest Airlines flights, 35% are US Airways flights, and 25% are JetBlue

flights.

a) Develop a joint probability table with three rows (airlines) and two columns (on-time arrivals

vs. late arrivals).

b) An announcement has just been made that Flight 1424 will be arriving at gate 20 in concourse

A. What is the most likely airline for this arrival?

c) What is the probability that Flight 1424 will arrive on time?

d) Suppose that an announcement is made saying that Flight 1424 will be arriving late. What is

the most likely airline for this arrival? What is the least likely airline?

............................................................................................................................................................

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THE INTERNATIONAL UNIVERSITY– VIETNAM NATIONAL UNIVERSITY – HCMC SCHOOL OF BUSINESS MID-TERM EXAMINATION Date: Duration: 90 minutes
Student ID: ..................................
Name:................................................
SUBJECT: Statistic for Business Dean of School Lecturers Signature: Signature: Dr. Le Van Chon Dr. Nguyen Ba Trung Mr. Nguyen Hoang Phu GENERAL INSTRUCTION(S) 1.
Students can bring only 1 note A4 (2-sides, handwriting) and calculator 2.
Other electronic decides are strictly prohibited 3.
No Discussion and sharing Materials.
PLEASE ANSWER DIRECTLY ON THIS SHEET 1
Please round the result to 4 decimals place, e.x 0.0001 Question 1: (25 pts)
To estimate which presidential candidate will be selected in the upcoming U.S election, BBC
news has conducted a survey of U.S voters. BBC has selected randomly 3 states in the U.S,
including: New York, Washington DC, and Montana. For each selected state, BBC has phoned
randomly 1000 voters about the following information: their age, their income (measured as: less
than $5.000 per month, from $5.000 - $10.000 per month, and above $10.000 per month), their
job, and who they plan to vote for in the upcoming presidential election.
a. What is the population in this study? What is the sample in this study? (5pts)
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b. What is the sampling method used in this study? (5pts)
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c. What is the variables in this study? What type of the data is each variable (Quantitative or Categorical) (5pts)?
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d.What is each variable’ level of measurement? (5pts)
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e. Is there the BBC study primarily an example of inferential or descriptive statistics? Why? (5pts)
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........................................................................................................................................................ Question 2 (15pts)
The figure 1 below presents the relationship between wage (million VND per month) and
education (years of schooling) of 20 workers.
Figure 1. The relationship between wage and education 3
a. Comment on the relationship between wage and education in Figure 1? If compute the
correlation between wage and education, what is the sign of the correlation coefficient (positive or negative)? (5pts).
............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
b. Using the above data, a researcher estimates a linear equation describing relationship between
wage and education as follows: Wage = 5.21 + 0.74*Education. Let a = 5.21, and b = 0.74,
Explain the meaning of a and b? (5pts)
............................................................................................................................................................
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............................................................................................................................................................
............................................................................................................................................................
............................................................................................................................................................
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c. Suppose that worker A has 10 years of schooling while worker B has 5 years of schooling. What
is the predicted difference in monthly wage between A and B? (5pts)
.............................................................................................................................................................
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.......................................................................................................................................................... ..
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........................................................................................................................................................ Question 3 (35 points)
Suppose that you are a research assistant at a market research company , you study about have a data set as below: 15 23 15 45 78 89 18 21 42 15 65 120
a. Calculate GeoMean; Mean, Median ; Mode; midrange
b. Calculate the sample standard deviation
c. Estimate the value of the 62% percentile
d. Calculate Interquartile range
e. According to Chebyshev’s Theorem, determine the interval that at least 75% number of population data belongs to ?
f. Suppose the dataset is a population, is the observation with its value of “120” an outlier point ? 4
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............................................................................................................................................................ Question 4: (5 pts) 5
Suppose a certain country has an experiment to test a Covid-19 vaccine with two groups : 70%
of participants received the vaccine (in the Group A ) and 30% of that did not receive the
vaccine (in the Group B) . After a test, for the Group A & B , the probability of “a negative
result” is 90% and 60% in respectively. If a person gets “ a negative result” , what is a
probability that she/he came from the Group A ? (5)
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............................................................................................................................................................ Question 5 : (20 pts)
The U.S. Department of Transportation reported that during November, 83.4% of Southwest
Airlines’ flights, 75.1% of US Airways’ flights, and 70.1% of JetBlue’s flights arrived on time
(USA Today, January 4, 2007). Assume that this on-time performance is applicable for flights
arriving at concourse A of the Rochester International Airport, and that 40% of the arrivals at
concourse A are Southwest Airlines flights, 35% are US Airways flights, and 25% are JetBlue flights.
a) Develop a joint probability table with three rows (airlines) and two columns (on-time arrivals vs. late arrivals).
b) An announcement has just been made that Flight 1424 will be arriving at gate 20 in concourse
A. What is the most likely airline for this arrival?
c) What is the probability that Flight 1424 will arrive on time?
d) Suppose that an announcement is made saying that Flight 1424 will be arriving late. What is
the most likely airline for this arrival? What is the least likely airline? 6
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