2025/2026 – Complete Questions
with 100% Verified Correct Answers
and Detailed Explanations Prepared for
Straighterline Introduction to Statistics Course Updated for
2025/2026 Academic Year
July 19, 2025
,Contents
1 Introduction 4
2 Question Categories 4
3 Questions, Answers, and Explanations 4
3.1 Descriptive Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1.1 Question 1: What is the primary objective of descriptive statis-
tics in data analysis? . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1.2 Question 2: Which concept is not associated with descriptive
statistics? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1.3 Question 3: A survey of 200 employees rates a company’s
culture as follows: 15% excellent, 25% good, 40% average,
20% poor. What does this summary suggest about employee
perceptions? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1.4 Question 4: Calculate the mean of the dataset: 10, 12, 8, 15, 5. 5
3.1.5 Question 5: Determine the median of the dataset: 9, 3, 7, 1, 11. 5
3.1.6 Question 6: What is the standard deviation of the dataset: 2,
4, 6, 8, 10? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3.1.7 Question 7: Find the mode of the dataset: 5, 7, 7, 9, 10, 10, 10. 6
3.1.8 Question 8: What information does a box plot primarily con-
vey about a dataset? . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.1.9 Question 9: If a dataset has a variance of 36, what is its stan-
dard deviation? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.1.10 Question 10: What is the range of the dataset: 20, 14, 8, 25, 10? 6
3.1.11 Question 11: What is the interquartile range (IQR) of the
dataset: 1, 3, 5, 7, 9? . . . . . . . . . . . . . . . . . . . . . . . . . . 6
3.1.12 Question 12: What does a left-skewed distribution indicate
about a dataset? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1.13 Question 13: Calculate the variance of the dataset: 4, 6, 8, 10. 7
3.1.14 Question 14: What is the primary use of a histogram in data
analysis? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1.15 Question 15: If a dataset has a mean of 15 and a median of
18, what is the likely shape of the distribution? . . . . . . . . . 7
3.1.16 Question 16: What is the coefficient of variation for a dataset
with a mean of 50 and a standard deviation of 5? . . . . . . . 7
3.1.17 Question 17: What is the purpose of a frequency table in
descriptive statistics? . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.1.18 Question 18: Calculate the midrange of the dataset: 12, 18,
24, 30, 36. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.1.19 Question 19: What does a high standard deviation indicate
about a dataset? . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.1.20 Question 20: What is the purpose of a stem-and-leaf plot? . . 8
3.2 Probability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.2.1 Question 21: What is the probability of rolling a 3 on a fair
six-sided die? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
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, 3.2.2 Question 22: If P(A) = 0.5 and P(B) = 0.6, and A and B are
independent, what is P(A and B)? . . . . . . . . . . . . . . . . . 9
3.2.3 Question 23: What is the probability of drawing a diamond
from a standard 52-card deck? . . . . . . . . . . . . . . . . . . . 9
3.2.4 Question 24: If P(A) = 0.7 and P(B) = 0.4, and A and B are
mutually exclusive, what is P(A or B)? . . . . . . . . . . . . . . 9
3.2.5 Question 25: What is the expected value of rolling a fair six-
sided die? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2.6 Question 26: In a binomial experiment with n=5 and p=0.3,
what is the probability of exactly 2 successes? . . . . . . . . . 9
3.2.7 Question 27: What is the probability of getting at least one
head in three coin flips? . . . . . . . . . . . . . . . . . . . . . . . 9
3.2.8 Question 28: What is a defining characteristic of a normal
distribution? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.2.9 Question 29: If a random variable follows a normal distribu-
tion with mean 100 and standard deviation 15, what is the
z-score for a value of 115? . . . . . . . . . . . . . . . . . . . . . . 10
3.2.10 Question 30: What is the probability of a value lying within
one standard deviation of the mean in a normal distribution? 10
3.2.11 Question 31: What is the probability of drawing an ace from
a standard 52-card deck? . . . . . . . . . . . . . . . . . . . . . . 10
3.2.12 Question 32: If P(A) = 0.6 and P(B|A) = 0.5, what is P(A and B)? 10
3.2.13 Question 33: What is the probability of rolling a number
greater than 4 on a six-sided die? . . . . . . . . . . . . . . . . . 10
3.2.14 Question 34: In a binomial experiment with n=4 and p=0.4,
what is the probability of exactly 3 successes? . . . . . . . . . 11
3.2.15 Question 35: What is the probability of the complement of
an event with P(A) = 0.25? . . . . . . . . . . . . . . . . . . . . . . 11
3.2.16 Question 36: What is the probability of getting exactly two
heads in four coin flips? . . . . . . . . . . . . . . . . . . . . . . . 11
3.2.17 Question 37: What is the variance of a binomial distribution
with n=10 and p=0.2? . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.2.18 Question 38: What does a Poisson distribution model in prob-
ability? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.2.19 Question 39: If a random variable is normally distributed
with mean 70 and standard deviation 10, what is P(X < 60)? . 11
3.2.20 Question 40: What is the probability of a value between one
and two standard deviations above the mean in a normal
distribution? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.3 Data Types and Measurement . . . . . . . . . . . . . . . . . . . . . . . . 12
3.3.1 Question 41: What level of measurement is used for ranking
students as first, second, or third in a competition? . . . . . . 12
3.3.2 Question 42: Which of the following variables is an example
of a nominal scale? . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.4 Inferential Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.5 Regression and Correlation . . . . . . . . . . . . . . . . . . . . . . . . . 18
4 Study Tips and Exam Preparation 21
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