WGU C955 Probability and Statistics Objective Assessment Exam
(2026/2027) with Questions and Revised Answers, 100% Guarantee
Pass (Updated) 2026/2027
STUVIAACTUALEXAM
Number of Questions: STUVIAACTUALEXAM
Passing Score: 75%
Exam Type: Multiple Choice
Sections:
1. Descriptive Statistics (14 Questions)
2. Probability (14 Questions)
3. Discrete Probability Distributions (14 Questions)
4. Continuous Probability Distributions (14 Questions)
5. Inferential Statistics (14 Questions)
This document contains the complete exam and answer key.
Good luck!
,Descriptive Statistics
Q1. A quality control engineer measures 12 machine bolt diameters in millimeters: 10.2, 10.5, 10.1,
10.4, 10.3, 10.6, 10.2, 10.5, 10.3, 10.4, 10.2, 10.5. What is the arithmetic mean diameter?
A. 10.35 mm
B. 10.40 mm
C. 10.25 mm
D. 10.50 mm
Q2. A hospital tracks daily emergency room visits over two weeks: 45, 48, 42, 120, 44, 46, 43, 47, 45, 49,
44, 46, 45, 48. Which measure best represents typical daily volume while minimizing the impact of the
unusual surge?
A. The median of 45.5 visits
B. The mean of 50.4 visits
C. The mode of 45 visits
D. The midrange of 81 visits
Q3. A retail store records shoe sizes sold during a weekend sale: 7, 8, 9, 8, 7, 8, 10, 8, 9, 8, 7, 8, 8, 9, 8.
What is the mode of this distribution?
A. Size 8
B. Size 7
C. Size 9
D. Size 10
Q4. A student receives grades: Homework (weight 20%, score 85), Midterm (weight 30%, score 80),
Final exam (weight 50%, score 90). What is the weighted average grade?
A. 86.0
B. 85.0
C. 88.5
D. 84.3
Q5. A biologist measures weights of 8 laboratory mice in grams: 18, 22, 19, 21, 20, 23, 18, 20. What is
the sample standard deviation?
A. 1.69 grams
B. 2.50 grams
C. 1.85 grams
D. 1.41 grams
Q6. A teacher records test scores of 10 students: 72, 85, 88, 90, 65, 78, 92, 85, 80, 75. What is the
sample variance?
A. 68.4
B. 75.2
C. 62.8
D. 58.6
, Q7. A human resources analyst collects salary data for 50 entry-level positions and finds the 75th
percentile is $48,000. What does this value indicate?
A. 75% of the salaries are at or below $48,000
B. The average salary is $48,000
C. 75% of salaries are above $48,000
D. The median salary is $48,000
Q8. A psychologist collects response times from 20 participants: Q1 = 245 ms, Q3 = 385 ms, median =
310 ms. What is the interquartile range (IQR)?
A. 140 ms
B. 155 ms
C. 175 ms
D. 120 ms
Q9. A manufacturing inspector constructs a box plot for breaking strengths of 30 cables. Whiskers
extend to 120 N and 280 N, box spans 180 N to 240 N, median is 210 N. What is the upper boundary
for identifying outliers using the 1.5*IQR rule?
A. 330 N
B. 300 N
C. 360 N
D. 280 N
Q10. A financial analyst examines annual stock returns over 10 years: 8%, -2%, 12%, 5%, 15%, 3%,
10%, -5%, 7%, 9%. The mean is 6.2% and the median is 7.5%. What does the relationship between
mean and median suggest?
A. The distribution is negatively skewed
B. The distribution is symmetric
C. The distribution is positively skewed
D. The distribution is uniform
Q11. A nurse compares two blood pressure monitors. Monitor A has SD 4.2 mmHg with mean 120
mmHg. Monitor B has SD 3.8 mmHg with mean 95 mmHg. Which monitor has greater relative
variability?
A. Monitor A with CV of 3.5%
B. Monitor B with CV of 4.0%
C. Both have equal variability
D. Cannot be determined from the given data
Q12. A transportation planner records bus arrival times. The mean is 8.5 minutes with SD 1.2
minutes. What is the z-score for a bus arriving in 10.9 minutes?
A. 2.0
B. 1.5
C. 2.5
D. 1.8
Q13. A standardized test has scores approximately normally distributed with mean 500 and SD 100.
(2026/2027) with Questions and Revised Answers, 100% Guarantee
Pass (Updated) 2026/2027
STUVIAACTUALEXAM
Number of Questions: STUVIAACTUALEXAM
Passing Score: 75%
Exam Type: Multiple Choice
Sections:
1. Descriptive Statistics (14 Questions)
2. Probability (14 Questions)
3. Discrete Probability Distributions (14 Questions)
4. Continuous Probability Distributions (14 Questions)
5. Inferential Statistics (14 Questions)
This document contains the complete exam and answer key.
Good luck!
,Descriptive Statistics
Q1. A quality control engineer measures 12 machine bolt diameters in millimeters: 10.2, 10.5, 10.1,
10.4, 10.3, 10.6, 10.2, 10.5, 10.3, 10.4, 10.2, 10.5. What is the arithmetic mean diameter?
A. 10.35 mm
B. 10.40 mm
C. 10.25 mm
D. 10.50 mm
Q2. A hospital tracks daily emergency room visits over two weeks: 45, 48, 42, 120, 44, 46, 43, 47, 45, 49,
44, 46, 45, 48. Which measure best represents typical daily volume while minimizing the impact of the
unusual surge?
A. The median of 45.5 visits
B. The mean of 50.4 visits
C. The mode of 45 visits
D. The midrange of 81 visits
Q3. A retail store records shoe sizes sold during a weekend sale: 7, 8, 9, 8, 7, 8, 10, 8, 9, 8, 7, 8, 8, 9, 8.
What is the mode of this distribution?
A. Size 8
B. Size 7
C. Size 9
D. Size 10
Q4. A student receives grades: Homework (weight 20%, score 85), Midterm (weight 30%, score 80),
Final exam (weight 50%, score 90). What is the weighted average grade?
A. 86.0
B. 85.0
C. 88.5
D. 84.3
Q5. A biologist measures weights of 8 laboratory mice in grams: 18, 22, 19, 21, 20, 23, 18, 20. What is
the sample standard deviation?
A. 1.69 grams
B. 2.50 grams
C. 1.85 grams
D. 1.41 grams
Q6. A teacher records test scores of 10 students: 72, 85, 88, 90, 65, 78, 92, 85, 80, 75. What is the
sample variance?
A. 68.4
B. 75.2
C. 62.8
D. 58.6
, Q7. A human resources analyst collects salary data for 50 entry-level positions and finds the 75th
percentile is $48,000. What does this value indicate?
A. 75% of the salaries are at or below $48,000
B. The average salary is $48,000
C. 75% of salaries are above $48,000
D. The median salary is $48,000
Q8. A psychologist collects response times from 20 participants: Q1 = 245 ms, Q3 = 385 ms, median =
310 ms. What is the interquartile range (IQR)?
A. 140 ms
B. 155 ms
C. 175 ms
D. 120 ms
Q9. A manufacturing inspector constructs a box plot for breaking strengths of 30 cables. Whiskers
extend to 120 N and 280 N, box spans 180 N to 240 N, median is 210 N. What is the upper boundary
for identifying outliers using the 1.5*IQR rule?
A. 330 N
B. 300 N
C. 360 N
D. 280 N
Q10. A financial analyst examines annual stock returns over 10 years: 8%, -2%, 12%, 5%, 15%, 3%,
10%, -5%, 7%, 9%. The mean is 6.2% and the median is 7.5%. What does the relationship between
mean and median suggest?
A. The distribution is negatively skewed
B. The distribution is symmetric
C. The distribution is positively skewed
D. The distribution is uniform
Q11. A nurse compares two blood pressure monitors. Monitor A has SD 4.2 mmHg with mean 120
mmHg. Monitor B has SD 3.8 mmHg with mean 95 mmHg. Which monitor has greater relative
variability?
A. Monitor A with CV of 3.5%
B. Monitor B with CV of 4.0%
C. Both have equal variability
D. Cannot be determined from the given data
Q12. A transportation planner records bus arrival times. The mean is 8.5 minutes with SD 1.2
minutes. What is the z-score for a bus arriving in 10.9 minutes?
A. 2.0
B. 1.5
C. 2.5
D. 1.8
Q13. A standardized test has scores approximately normally distributed with mean 500 and SD 100.
