DA0-002 Visualization and Reporting Practice Question
A data analyst creates a dashboard showing average order value by region. The chart indicates that one region has an unusually high average. Investigation reveals that the region has very few orders, but one large purchase inflates the average. Which data transformation should the analyst apply to improve the visualization?
⚠ Common exam trap
The trap is that candidates focus on visual fixes (log scale, chart type) when the real issue is the statistical aggregation; the exam tests whether you recognize mean vs. median robustness to outliers.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use median instead of mean for aggregation
The mean is highly sensitive to extreme values, so a single large purchase in a region with few orders skews the average upward and misrepresents the typical order value. The median is a robust measure of central tendency that resists outlier influence, so switching the aggregation from mean to median gives a truer picture of typical order value per region.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Apply logarithmic scaling to the y-axis
Why it's wrong here
Logarithmic scaling compresses the y-axis range, so the outlier still skews the plotted average; it does not change the computed value. It is tempting because log scales suit data spanning orders of magnitude, such as exponentially growing counts, but here the fix is a robust statistic like the median or filtering low-volume regions.
- ✓
Use median instead of mean for aggregation
Why this is correct
The mean is skewed by that single large purchase because the region has few orders, so it no longer represents typical order value. The median resists outliers, giving a central value that reflects the region's actual orders and corrects the inflated chart.
- ✗
Change the chart type to a pie chart
Why it's wrong here
A pie chart shows parts of a whole, not averages, so it cannot display average order value by region at all. Pie charts are the right choice for proportional composition of a single total across categories.
- ✗
Remove all outliers from the dataset
Why it's wrong here
Removing outliers may discard valid data; better to use robust aggregation.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official CompTIA exam blueprint
This DA0-002 practice question is part of Courseiva's free CompTIA certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DA0-002 exam.