WGU D089 — Objective Assessment (OA) | Data-Driven Decision Making 2026 Update | 70 Questions | 100 pts
WGU D089 OBJECTIVE ASSESSMENT (OA)
70 ACTUAL QUESTIONS AND ANSWERS | 2026 UPDATE | WITH COMPLETE SOLUTIONS
Western Governors University • Data-Driven Decision Making (D089)
Aligned with 2026 | 2027 academic standards • Business Analytics & Business Intelligence
Questions 70 multiple-choice (4 sections) Time (suggested) 120 minutes
Points 100 (~1.43 pts per question) Passing ≥ 70 (Competent)
Cognitive Mix 30% recall · 50% application · 20% analysis Format 75% scenario / 25% direct
Examination Instructions
This Objective Assessment mirrors the structure, rigor, and business-application style of the actual WGU D089
OA. Each question presents four options (A–D) with exactly one correct answer. Rationales include
step-by-step statistical derivations—hypothesis-test setups, probability calculations, and regression
interpretations—and explicitly identify the conceptual errors that produce each distractor. Section 4 integrates
2026|2027 modern analytics contexts including AI-driven predictive modeling, AutoML, contemporary data
visualization, and modern data-governance frameworks.
Section 1: Descriptive Statistics, Data Visualization, & Probability (Q1–Q18)
Measures of central tendency and dispersion; data visualization (histograms, box plots, scatter plots, bar/pie
charts); and fundamental probability rules (addition, multiplication, conditional probability, Bayes' theorem).
Q1. A retail chain recorded weekly sales of $4,200, $4,800, $5,100, $4,500, and $5,400. What is the median
weekly sales?
A. $4,800 [CORRECT]
B. $4,920
C. $4,500
D. $5,100
Correct Answer: A — $4,800
Rationale: Ordered: 4200, 4500, 4800, 5100, 5400. The middle value (3rd of 5) is $4,800. B is the mean (sum/5 =
24,600/5 = 4920); C is the 2nd value; D is the 4th value.
Q2. Executive salaries at a startup are highly right-skewed because the CEO earns 20× the median employee.
Which measure best summarizes the typical executive salary?
A. Median [CORRECT]
B. Mean
C. Range
D. Standard deviation
Correct Answer: A — Median
Rationale: The median is resistant to extreme outliers and best represents the center of skewed data. B is inflated by
the CEO's salary; C measures spread, not center; D also measures spread.
Q3. A call center logs wait times (minutes): 2, 3, 3, 4, 5, 5, 5, 6, 7, 25. What is the mode?
A. 5 [CORRECT]
B. 6.5
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,WGU D089 — Objective Assessment (OA) | Data-Driven Decision Making 2026 Update | 70 Questions | 100 pts
C. 3
D. 25
Correct Answer: A — 5
Rationale: The value 5 appears three times, more than any other value. B is the median; C is the
second-most-frequent; D is the maximum (an outlier).
Q4. A student's GPA: A (4.0) in 4 credits, B (3.0) in 3 credits, C (2.0) in 2 credits, A (4.0) in 1 credit. Compute
the GPA.
A. 3.40 [CORRECT]
B. 3.25
C. 3.00
D. 4.00
Correct Answer: A — 3.40
Rationale: Weighted mean = (4·4 + 3·3 + 2·2 + 1·4)/(4+3+2+1) = (16+9+4+4)/10 = 33/10 = 3.40. B is the simple
unweighted mean; C ignores the weights; D assumes all A's.
Q5. A mutual fund returned +25%, -10%, and +5% over three years. The geometric mean return is:
A. ≈ 5.67% [CORRECT]
B. 6.67%
C. 5.00%
D. 10.00%
Correct Answer: A — ≈ 5.67%
Rationale: Geometric mean = [(1.25)(0.90)(1.05)]^(1/3) - 1 = (1.18125)^(1/3) - 1 ≈ 5.67%. B is the arithmetic mean,
which overstates compounded growth; C ignores two of the three returns; D uses only the first year.
Q6. For the dataset {10, 20, 30, 40, 50}, compute the range and midrange.
A. Range = 40, Midrange = 30 [CORRECT]
B. Range = 30, Midrange = 40
C. Range = 40, Midrange = 40
D. Range = 50, Midrange = 30
Correct Answer: A — Range = 40, Midrange = 30
Rationale: Range = max - min = 50 - 10 = 40; midrange = (max + min)/2 = (50+10)/2 = 30. B swaps the two; C
miscomputes midrange; D uses max as the range.
Q7. For the population data {4, 8, 12, 16}, compute the population variance.
A. 20 [CORRECT]
B. 26.67
C. 4.47
D. 10
Correct Answer: A — 20
Rationale: Mean = 10; squared deviations = 36, 4, 4, 36; sum = 80; population variance = 80/4 = 20. B divides by n-1 =
3 (sample variance error); C is the SD √20; D miscalculates the sum.
Q8. A quality-control chart shows the standard deviation of bolt diameters is 0.000 mm. This implies:
A. All bolts have identical diameter [CORRECT]
B. The mean diameter is 0
C. The sample size is 1
D. The data is normally distributed
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, WGU D089 — Objective Assessment (OA) | Data-Driven Decision Making 2026 Update | 70 Questions | 100 pts
Correct Answer: A — All bolts have identical diameter
Rationale: A standard deviation of exactly 0 means every value equals the mean, so all bolts have identical
diameter. B confuses SD with mean; C is unrelated; D cannot be inferred from SD alone.
Q9. Stock X: mean return 8%, SD 4%. Stock Y: mean return 12%, SD 9%. Which has higher relative variability
(coefficient of variation)?
A. Stock Y (CV = 75%) [CORRECT]
B. Stock X (CV = 50%)
C. Both are equal
D. Cannot be determined
Correct Answer: A — Stock Y (CV = 75%)
Rationale: CV_X = 4/8 = 50%; CV_Y = 9/12 = 75%. Stock Y has higher relative variability. B compares absolute SDs
instead of relative; C ignores the difference; D fails to compute CVs.
Q10. Dataset: {2, 4, 6, 8, 10, 12, 14, 100}. Using the IQR method (1.5×IQR fence), identify outliers.
A. 100 is an outlier [CORRECT]
B. No outliers exist
C. 2 is an outlier
D. Both 2 and 100 are outliers
Correct Answer: A — 100 is an outlier
Rationale: Q1 = 5, Q3 = 13, IQR = 8; upper fence = 13 + 1.5(8) = 25. Since 100 > 25, 100 is an outlier. B ignores the
fence test; C is above the lower fence of -7; D double-counts.
Q11. A box plot has its median line shifted toward Q3 and a long lower whisker. The distribution is:
A. Left-skewed [CORRECT]
B. Right-skewed
C. Symmetric
D. Uniform
Correct Answer: A — Left-skewed
Rationale: A long lower whisker with the median pulled toward Q3 indicates left-skew (tail extends left). B reverses the
direction; C requires symmetric whiskers; D implies a flat shape.
Q12. Find the five-number summary for {5, 7, 9, 11, 13, 15, 17}.
A. 5, 8, 11, 14, 17 [CORRECT]
B. 5, 7, 11, 15, 17
C. 5, 9, 11, 13, 17
D. 5, 8, 11, 13, 17
Correct Answer: A — 5, 8, 11, 14, 17
Rationale: Min=5, Q1=median of {5,7,9}=7... but with 7 values, Q1 = median of lower half {5,7,9,11} (exclusive) = 8;
median = 11; Q3 = median of {11,13,15,17} = 14; max = 17 → 5, 8, 11, 14, 17. B/C/D miscompute quartiles using
different conventions.
Q13. A student scores 720 on the GMAT, placing them at the 85th percentile. This means:
A. The student scored higher than 85% of test takers [CORRECT]
B. The student answered 85% of questions correctly
C. The raw score is 85
D. 85% of students scored exactly 720
Correct Answer: A — The student scored higher than 85% of test takers
Western Governors University • Confidential OA Study Tool Page 3
WGU D089 OBJECTIVE ASSESSMENT (OA)
70 ACTUAL QUESTIONS AND ANSWERS | 2026 UPDATE | WITH COMPLETE SOLUTIONS
Western Governors University • Data-Driven Decision Making (D089)
Aligned with 2026 | 2027 academic standards • Business Analytics & Business Intelligence
Questions 70 multiple-choice (4 sections) Time (suggested) 120 minutes
Points 100 (~1.43 pts per question) Passing ≥ 70 (Competent)
Cognitive Mix 30% recall · 50% application · 20% analysis Format 75% scenario / 25% direct
Examination Instructions
This Objective Assessment mirrors the structure, rigor, and business-application style of the actual WGU D089
OA. Each question presents four options (A–D) with exactly one correct answer. Rationales include
step-by-step statistical derivations—hypothesis-test setups, probability calculations, and regression
interpretations—and explicitly identify the conceptual errors that produce each distractor. Section 4 integrates
2026|2027 modern analytics contexts including AI-driven predictive modeling, AutoML, contemporary data
visualization, and modern data-governance frameworks.
Section 1: Descriptive Statistics, Data Visualization, & Probability (Q1–Q18)
Measures of central tendency and dispersion; data visualization (histograms, box plots, scatter plots, bar/pie
charts); and fundamental probability rules (addition, multiplication, conditional probability, Bayes' theorem).
Q1. A retail chain recorded weekly sales of $4,200, $4,800, $5,100, $4,500, and $5,400. What is the median
weekly sales?
A. $4,800 [CORRECT]
B. $4,920
C. $4,500
D. $5,100
Correct Answer: A — $4,800
Rationale: Ordered: 4200, 4500, 4800, 5100, 5400. The middle value (3rd of 5) is $4,800. B is the mean (sum/5 =
24,600/5 = 4920); C is the 2nd value; D is the 4th value.
Q2. Executive salaries at a startup are highly right-skewed because the CEO earns 20× the median employee.
Which measure best summarizes the typical executive salary?
A. Median [CORRECT]
B. Mean
C. Range
D. Standard deviation
Correct Answer: A — Median
Rationale: The median is resistant to extreme outliers and best represents the center of skewed data. B is inflated by
the CEO's salary; C measures spread, not center; D also measures spread.
Q3. A call center logs wait times (minutes): 2, 3, 3, 4, 5, 5, 5, 6, 7, 25. What is the mode?
A. 5 [CORRECT]
B. 6.5
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,WGU D089 — Objective Assessment (OA) | Data-Driven Decision Making 2026 Update | 70 Questions | 100 pts
C. 3
D. 25
Correct Answer: A — 5
Rationale: The value 5 appears three times, more than any other value. B is the median; C is the
second-most-frequent; D is the maximum (an outlier).
Q4. A student's GPA: A (4.0) in 4 credits, B (3.0) in 3 credits, C (2.0) in 2 credits, A (4.0) in 1 credit. Compute
the GPA.
A. 3.40 [CORRECT]
B. 3.25
C. 3.00
D. 4.00
Correct Answer: A — 3.40
Rationale: Weighted mean = (4·4 + 3·3 + 2·2 + 1·4)/(4+3+2+1) = (16+9+4+4)/10 = 33/10 = 3.40. B is the simple
unweighted mean; C ignores the weights; D assumes all A's.
Q5. A mutual fund returned +25%, -10%, and +5% over three years. The geometric mean return is:
A. ≈ 5.67% [CORRECT]
B. 6.67%
C. 5.00%
D. 10.00%
Correct Answer: A — ≈ 5.67%
Rationale: Geometric mean = [(1.25)(0.90)(1.05)]^(1/3) - 1 = (1.18125)^(1/3) - 1 ≈ 5.67%. B is the arithmetic mean,
which overstates compounded growth; C ignores two of the three returns; D uses only the first year.
Q6. For the dataset {10, 20, 30, 40, 50}, compute the range and midrange.
A. Range = 40, Midrange = 30 [CORRECT]
B. Range = 30, Midrange = 40
C. Range = 40, Midrange = 40
D. Range = 50, Midrange = 30
Correct Answer: A — Range = 40, Midrange = 30
Rationale: Range = max - min = 50 - 10 = 40; midrange = (max + min)/2 = (50+10)/2 = 30. B swaps the two; C
miscomputes midrange; D uses max as the range.
Q7. For the population data {4, 8, 12, 16}, compute the population variance.
A. 20 [CORRECT]
B. 26.67
C. 4.47
D. 10
Correct Answer: A — 20
Rationale: Mean = 10; squared deviations = 36, 4, 4, 36; sum = 80; population variance = 80/4 = 20. B divides by n-1 =
3 (sample variance error); C is the SD √20; D miscalculates the sum.
Q8. A quality-control chart shows the standard deviation of bolt diameters is 0.000 mm. This implies:
A. All bolts have identical diameter [CORRECT]
B. The mean diameter is 0
C. The sample size is 1
D. The data is normally distributed
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, WGU D089 — Objective Assessment (OA) | Data-Driven Decision Making 2026 Update | 70 Questions | 100 pts
Correct Answer: A — All bolts have identical diameter
Rationale: A standard deviation of exactly 0 means every value equals the mean, so all bolts have identical
diameter. B confuses SD with mean; C is unrelated; D cannot be inferred from SD alone.
Q9. Stock X: mean return 8%, SD 4%. Stock Y: mean return 12%, SD 9%. Which has higher relative variability
(coefficient of variation)?
A. Stock Y (CV = 75%) [CORRECT]
B. Stock X (CV = 50%)
C. Both are equal
D. Cannot be determined
Correct Answer: A — Stock Y (CV = 75%)
Rationale: CV_X = 4/8 = 50%; CV_Y = 9/12 = 75%. Stock Y has higher relative variability. B compares absolute SDs
instead of relative; C ignores the difference; D fails to compute CVs.
Q10. Dataset: {2, 4, 6, 8, 10, 12, 14, 100}. Using the IQR method (1.5×IQR fence), identify outliers.
A. 100 is an outlier [CORRECT]
B. No outliers exist
C. 2 is an outlier
D. Both 2 and 100 are outliers
Correct Answer: A — 100 is an outlier
Rationale: Q1 = 5, Q3 = 13, IQR = 8; upper fence = 13 + 1.5(8) = 25. Since 100 > 25, 100 is an outlier. B ignores the
fence test; C is above the lower fence of -7; D double-counts.
Q11. A box plot has its median line shifted toward Q3 and a long lower whisker. The distribution is:
A. Left-skewed [CORRECT]
B. Right-skewed
C. Symmetric
D. Uniform
Correct Answer: A — Left-skewed
Rationale: A long lower whisker with the median pulled toward Q3 indicates left-skew (tail extends left). B reverses the
direction; C requires symmetric whiskers; D implies a flat shape.
Q12. Find the five-number summary for {5, 7, 9, 11, 13, 15, 17}.
A. 5, 8, 11, 14, 17 [CORRECT]
B. 5, 7, 11, 15, 17
C. 5, 9, 11, 13, 17
D. 5, 8, 11, 13, 17
Correct Answer: A — 5, 8, 11, 14, 17
Rationale: Min=5, Q1=median of {5,7,9}=7... but with 7 values, Q1 = median of lower half {5,7,9,11} (exclusive) = 8;
median = 11; Q3 = median of {11,13,15,17} = 14; max = 17 → 5, 8, 11, 14, 17. B/C/D miscompute quartiles using
different conventions.
Q13. A student scores 720 on the GMAT, placing them at the 85th percentile. This means:
A. The student scored higher than 85% of test takers [CORRECT]
B. The student answered 85% of questions correctly
C. The raw score is 85
D. 85% of students scored exactly 720
Correct Answer: A — The student scored higher than 85% of test takers
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