DA0-002 Data Governance Practice Question
A data analyst creates a line chart showing monthly sales over the past year. The chart uses a y-axis starting at $100,000 instead of zero. What is the most likely misinterpretation a viewer might have?
⚠ Common exam trap
Test-takers frequently think a truncated y-axis only affects bar charts or that it reverses trends, but CompTIA often tests the specific misinterpretation that small changes appear exaggerated due to the loss of a zero baseline, not that the direction of the trend is flipped.
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
✓
The differences between months are exaggerated, making small changes look large.
Starting the y-axis at $100,000 instead of zero truncates the baseline, which visually exaggerates the relative differences between monthly sales values. This is a common data visualization pitfall that can mislead viewers into perceiving small fluctuations as significant trends, violating the principle of using a zero baseline for bar and line charts to accurately represent proportional change.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The differences between months are exaggerated, making small changes look large.
Why this is correct
A truncated y-axis compresses the visual distance that represents zero, so equal dollar gaps occupy unequal chart heights. Monthly variations therefore appear steeper than they are, exaggerating differences and making minor fluctuations look like significant shifts.
- ✗
The sales appear to be decreasing when they are actually increasing.
Why it's wrong here
A truncated y-axis does not reverse the trend; it exaggerates the magnitude.
- ✗
The chart is correctly scaled, so no misinterpretation occurs.
Why it's wrong here
Starting the y-axis at $100,000 compresses the visible range and magnifies month-to-month movement, so viewers overestimate changes; misinterpretation is likely, not absent. Zero-based axes are correct for bar charts, where truncated baselines distort the encoded lengths rather than merely the slope.
- ✗
The sales appear to be increasing when they are actually decreasing.
Why it's wrong here
Truncating the y-axis amplifies the visual slope of whatever trend exists; it cannot invert the direction of the underlying values. A decreasing series still descends. Non-zero baselines suit line charts tracking small fluctuations, where the analyst wants variation emphasised rather than absolute magnitude.
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
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.