STRAIGHTERLINE INTRODUCTION TO STATISTICS FINAL
EXAM 2026 AND STUDY GUIDE COMPLETE ACCURATE EXAM
ACTUAL QUESTIONS AND CORRECT DETAILED ANSWERS
WITH RATIONALES (100% EXPERT VERIFIED SOLUTIONS)
NEWEST UPDATED VERSION 2026 EDITION |GUARANTEED
SUCCESS + |BRAND NEW! |FULL REVISED
A researcher collects data on the heights of 100 randomly selected adult males.
The mean height is 175 cm with a standard deviation of 8 cm. What is the z-score
for a male with a height of 191 cm?
A. -2.00
B. 2.00
C. 2.00 CORRECT ANSWER
D. 16.00
Rationale: The z-score is calculated as (X - μ) / σ = (191 - 175) / 8 = = 2.00.
A positive z-score indicates the value is above the mean.
A six-sided die is rolled once. What is the probability of rolling a number greater
than 4?
A. 1/6
B. 1/3
C. 1/3 CORRECT ANSWER
D. 1/2
Rationale: Numbers greater than 4 are 5 and 6, so 2 favorable outcomes out of 6
possible: 2/6 = 1/3.
,In a normal distribution, approximately what percentage of data falls within one
standard deviation of the mean?
A. 68%
B. 68% CORRECT ANSWER
C. 95%
D. 99.7%
Rationale: The empirical rule states that for a normal distribution, about 68% of
values lie within ±1 standard deviation from the mean.
A sample of 50 students has an average test score of 78 with a sample standard
deviation of 10. Which of the following represents the 95% confidence interval for
the population mean? (Assume z* = 1.96)
A. 78 ± 1.96(10/√50)
B. 78 ± 1.96(10/√50) CORRECT ANSWER
C. 78 ± 1.96(10)
D. 78 ± 1.96(√50/10)
Rationale: The formula for a confidence interval for the mean when σ is unknown
but n≥30 is x̄ ± z*(s/√n). Here, standard error = 10/√50, so 78 ± 1.96*(10/√50).
Which of the following is a measure of central tendency?
A. Variance
B. Median CORRECT ANSWER
C. Range
D. Standard deviation
,Rationale: Measures of central tendency include mean, median, and mode.
Variance, range, and standard deviation are measures of dispersion.
A hypothesis test results in a p-value of 0.03. Using a significance level α = 0.05,
what is the correct decision?
A. Fail to reject H₀
B. Reject H₀ CORRECT ANSWER
C. Accept H₀
D. Reject H₁
Rationale: Since p-value (0.03) < α (0.05), we reject the null hypothesis. There is
sufficient evidence to support the alternative.
What is the median of the dataset: 3, 7, 9, 12, 15?
A. 7
B. 8
C. 9 CORRECT ANSWER
D. 12
Rationale: The median is the middle value when data are ordered. Here, the third
value is 9.
If two events are mutually exclusive, their joint probability P(A and B) equals:
A. P(A) * P(B)
B. P(A) + P(B)
C. 0 CORRECT ANSWER
D. 1
, Rationale: Mutually exclusive events cannot occur at the same time, so P(A and B)
= 0.
A survey finds that 40% of people prefer coffee over tea. If 5 people are randomly
selected, what is the probability that exactly 2 prefer coffee? (Use binomial
distribution)
A. 0.2304
B. 0.3456
C. 0.3456 CORRECT ANSWER
D. 0.2592
Rationale: Binomial probability: C(5,2)(0.4)^2(0.6)^3 = 10 * 0.16 * 0.216 =
0.3456.
In linear regression, the coefficient of determination (R²) measures:
A. The slope of the regression line
B. The correlation between X and Y
C. The proportion of variance in Y explained by X CORRECT ANSWER
D. The standard error of the estimate
Rationale: R² indicates the percentage of the dependent variable’s variation that the
independent variable(s) explain.
A boxplot shows the following five-number summary: Min=2, Q1=5, Median=8,
Q3=12, Max=18. What is the interquartile range (IQR)?
A. 3
EXAM 2026 AND STUDY GUIDE COMPLETE ACCURATE EXAM
ACTUAL QUESTIONS AND CORRECT DETAILED ANSWERS
WITH RATIONALES (100% EXPERT VERIFIED SOLUTIONS)
NEWEST UPDATED VERSION 2026 EDITION |GUARANTEED
SUCCESS + |BRAND NEW! |FULL REVISED
A researcher collects data on the heights of 100 randomly selected adult males.
The mean height is 175 cm with a standard deviation of 8 cm. What is the z-score
for a male with a height of 191 cm?
A. -2.00
B. 2.00
C. 2.00 CORRECT ANSWER
D. 16.00
Rationale: The z-score is calculated as (X - μ) / σ = (191 - 175) / 8 = = 2.00.
A positive z-score indicates the value is above the mean.
A six-sided die is rolled once. What is the probability of rolling a number greater
than 4?
A. 1/6
B. 1/3
C. 1/3 CORRECT ANSWER
D. 1/2
Rationale: Numbers greater than 4 are 5 and 6, so 2 favorable outcomes out of 6
possible: 2/6 = 1/3.
,In a normal distribution, approximately what percentage of data falls within one
standard deviation of the mean?
A. 68%
B. 68% CORRECT ANSWER
C. 95%
D. 99.7%
Rationale: The empirical rule states that for a normal distribution, about 68% of
values lie within ±1 standard deviation from the mean.
A sample of 50 students has an average test score of 78 with a sample standard
deviation of 10. Which of the following represents the 95% confidence interval for
the population mean? (Assume z* = 1.96)
A. 78 ± 1.96(10/√50)
B. 78 ± 1.96(10/√50) CORRECT ANSWER
C. 78 ± 1.96(10)
D. 78 ± 1.96(√50/10)
Rationale: The formula for a confidence interval for the mean when σ is unknown
but n≥30 is x̄ ± z*(s/√n). Here, standard error = 10/√50, so 78 ± 1.96*(10/√50).
Which of the following is a measure of central tendency?
A. Variance
B. Median CORRECT ANSWER
C. Range
D. Standard deviation
,Rationale: Measures of central tendency include mean, median, and mode.
Variance, range, and standard deviation are measures of dispersion.
A hypothesis test results in a p-value of 0.03. Using a significance level α = 0.05,
what is the correct decision?
A. Fail to reject H₀
B. Reject H₀ CORRECT ANSWER
C. Accept H₀
D. Reject H₁
Rationale: Since p-value (0.03) < α (0.05), we reject the null hypothesis. There is
sufficient evidence to support the alternative.
What is the median of the dataset: 3, 7, 9, 12, 15?
A. 7
B. 8
C. 9 CORRECT ANSWER
D. 12
Rationale: The median is the middle value when data are ordered. Here, the third
value is 9.
If two events are mutually exclusive, their joint probability P(A and B) equals:
A. P(A) * P(B)
B. P(A) + P(B)
C. 0 CORRECT ANSWER
D. 1
, Rationale: Mutually exclusive events cannot occur at the same time, so P(A and B)
= 0.
A survey finds that 40% of people prefer coffee over tea. If 5 people are randomly
selected, what is the probability that exactly 2 prefer coffee? (Use binomial
distribution)
A. 0.2304
B. 0.3456
C. 0.3456 CORRECT ANSWER
D. 0.2592
Rationale: Binomial probability: C(5,2)(0.4)^2(0.6)^3 = 10 * 0.16 * 0.216 =
0.3456.
In linear regression, the coefficient of determination (R²) measures:
A. The slope of the regression line
B. The correlation between X and Y
C. The proportion of variance in Y explained by X CORRECT ANSWER
D. The standard error of the estimate
Rationale: R² indicates the percentage of the dependent variable’s variation that the
independent variable(s) explain.
A boxplot shows the following five-number summary: Min=2, Q1=5, Median=8,
Q3=12, Max=18. What is the interquartile range (IQR)?
A. 3
