MATH 120 INTRODUCTION TO STATISTICS EXAM – QUESTIONS AND ANSWERS |
VERIFIED AND WELL DETAILED ANSWERS | PLUS RATIONALES | DOWNLOAD
AND PASS | LATEST EXAM UPDATE 2026/2027
Core Domains
Descriptive Statistics and Data Presentation
Probability Theory and Distributions
Sampling Methods and Central Limit Theorem
Confidence Interval Estimation
Hypothesis Testing (One and Two Samples)
Correlation and Linear Regression
Analysis of Variance (ANOVA)
Chi-Square Tests and Goodness of Fit
Ethics in Statistical Practice and Data Reporting
Introduction
This examination assesses comprehensive knowledge and applied skills in
introductory statistics. It evaluates understanding of descriptive measures, probability,
inferential techniques, and ethical data handling. Through multiple-choice and
scenario-based questions, candidates must demonstrate the ability to select
appropriate statistical methods, interpret results accurately, and apply statistical
reasoning to real-world professional decisions. The exam emphasizes critical
thinking, regulatory compliance in data reporting, and the practical application of
statistical concepts to solve problems across diverse fields. Successful completion
requires not only computational proficiency but also the ability to communicate
statistical findings clearly and ethically.
,SECTION ONE: QUESTIONS 1–50
Question 1
A researcher collects the ages of 50 participants in a study. The ages are: 22, 25, 28,
22, 30, 25, 22, 35, 40, 28, 25, 22, 30, 35, 28, 25, 40, 22, 30, 25, 28, 35, 22, 25, 30, 40,
28, 22, 25, 35, 30, 22, 28, 25, 40, 35, 30, 22, 25, 28, 35, 40, 30, 22, 25, 28, 35, 30, 22,
25. What is the mode of this dataset?
A. 25
B. 22
C. 28
D. 30
🟢 Correct Answer: B. 22
🔴 Explanation: The mode is the most frequently occurring value. Counting
frequencies: 22 appears 11 times, 25 appears 10 times, 28 appears 7 times, 30
appears 7 times, 35 appears 6 times, and 40 appears 4 times. The value 22 has the
highest frequency.
Question 2
Which measure of central tendency is most appropriate for a dataset that includes
extreme outliers?
A. Mean
B. Median
C. Mode
D. Range
🟢 Correct Answer: B. Median
,🔴 Explanation: The median is resistant to outliers because it depends on the
position of values rather than their magnitude. The mean is heavily influenced by
extreme values, while the mode and range do not measure central tendency
effectively in this context.
Question 3
A dataset has a standard deviation of 0. What can be concluded about the data?
A. The data is normally distributed.
B. All values in the dataset are identical.
C. The mean is zero.
D. The data contains outliers.
🟢 Correct Answer: B. All values in the dataset are identical.
🔴 Explanation: A standard deviation of zero indicates no variability; every
observation is equal to the mean. Therefore, all values must be identical.
Question 4
In a positively skewed distribution, which relationship between the mean, median,
and mode is typically true?
A. Mean = Median = Mode
B. Mean < Median < Mode
C. Mean > Median > Mode
D. Mode > Mean > Median
🟢 Correct Answer: C. Mean > Median > Mode
, 🔴 Explanation: In a positively skewed (right-skewed) distribution, the tail extends
to the right, pulling the mean to the right of the median, which is to the right of
the mode.
Question 5
A hospital administrator wants to summarize the average wait time for emergency
room patients. The wait times are severely right-skewed. Which measure should be
reported to best represent the typical wait time?
A. Mean
B. Median
C. Standard deviation
D. Variance
🟢 Correct Answer: B. Median
🔴 Explanation: For skewed data, the median is the preferred measure of central
tendency because it is not affected by extreme values. Reporting the mean would
overstate the typical wait time.
Question 6
What is the primary purpose of calculating the coefficient of variation (CV)?
A. To measure the shape of a distribution
B. To compare variability between datasets with different units or means
C. To determine the median of a dataset
D. To test for normality
VERIFIED AND WELL DETAILED ANSWERS | PLUS RATIONALES | DOWNLOAD
AND PASS | LATEST EXAM UPDATE 2026/2027
Core Domains
Descriptive Statistics and Data Presentation
Probability Theory and Distributions
Sampling Methods and Central Limit Theorem
Confidence Interval Estimation
Hypothesis Testing (One and Two Samples)
Correlation and Linear Regression
Analysis of Variance (ANOVA)
Chi-Square Tests and Goodness of Fit
Ethics in Statistical Practice and Data Reporting
Introduction
This examination assesses comprehensive knowledge and applied skills in
introductory statistics. It evaluates understanding of descriptive measures, probability,
inferential techniques, and ethical data handling. Through multiple-choice and
scenario-based questions, candidates must demonstrate the ability to select
appropriate statistical methods, interpret results accurately, and apply statistical
reasoning to real-world professional decisions. The exam emphasizes critical
thinking, regulatory compliance in data reporting, and the practical application of
statistical concepts to solve problems across diverse fields. Successful completion
requires not only computational proficiency but also the ability to communicate
statistical findings clearly and ethically.
,SECTION ONE: QUESTIONS 1–50
Question 1
A researcher collects the ages of 50 participants in a study. The ages are: 22, 25, 28,
22, 30, 25, 22, 35, 40, 28, 25, 22, 30, 35, 28, 25, 40, 22, 30, 25, 28, 35, 22, 25, 30, 40,
28, 22, 25, 35, 30, 22, 28, 25, 40, 35, 30, 22, 25, 28, 35, 40, 30, 22, 25, 28, 35, 30, 22,
25. What is the mode of this dataset?
A. 25
B. 22
C. 28
D. 30
🟢 Correct Answer: B. 22
🔴 Explanation: The mode is the most frequently occurring value. Counting
frequencies: 22 appears 11 times, 25 appears 10 times, 28 appears 7 times, 30
appears 7 times, 35 appears 6 times, and 40 appears 4 times. The value 22 has the
highest frequency.
Question 2
Which measure of central tendency is most appropriate for a dataset that includes
extreme outliers?
A. Mean
B. Median
C. Mode
D. Range
🟢 Correct Answer: B. Median
,🔴 Explanation: The median is resistant to outliers because it depends on the
position of values rather than their magnitude. The mean is heavily influenced by
extreme values, while the mode and range do not measure central tendency
effectively in this context.
Question 3
A dataset has a standard deviation of 0. What can be concluded about the data?
A. The data is normally distributed.
B. All values in the dataset are identical.
C. The mean is zero.
D. The data contains outliers.
🟢 Correct Answer: B. All values in the dataset are identical.
🔴 Explanation: A standard deviation of zero indicates no variability; every
observation is equal to the mean. Therefore, all values must be identical.
Question 4
In a positively skewed distribution, which relationship between the mean, median,
and mode is typically true?
A. Mean = Median = Mode
B. Mean < Median < Mode
C. Mean > Median > Mode
D. Mode > Mean > Median
🟢 Correct Answer: C. Mean > Median > Mode
, 🔴 Explanation: In a positively skewed (right-skewed) distribution, the tail extends
to the right, pulling the mean to the right of the median, which is to the right of
the mode.
Question 5
A hospital administrator wants to summarize the average wait time for emergency
room patients. The wait times are severely right-skewed. Which measure should be
reported to best represent the typical wait time?
A. Mean
B. Median
C. Standard deviation
D. Variance
🟢 Correct Answer: B. Median
🔴 Explanation: For skewed data, the median is the preferred measure of central
tendency because it is not affected by extreme values. Reporting the mean would
overstate the typical wait time.
Question 6
What is the primary purpose of calculating the coefficient of variation (CV)?
A. To measure the shape of a distribution
B. To compare variability between datasets with different units or means
C. To determine the median of a dataset
D. To test for normality
