DA0-002 Data Analysis Practice Question
A data analyst is analyzing customer purchase amounts. The dataset contains several extreme high values due to luxury purchases. Which measure of central tendency is most robust to these outliers?
⚠ Common exam trap
The trap is defaulting to the mean as 'the average' out of habit — candidates must recognize that 'robust to outliers' specifically signals the median, not the arithmetic mean.
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
✓
Median
The median is the middle value when data is ordered, so extreme high values (luxury purchases) shift it only slightly — it is a robust measure of central tendency. Unlike the mean, which is pulled upward by outliers because it sums all values, the median depends only on rank position. This makes it the preferred measure for skewed distributions like income or purchase amounts.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Range
Why it's wrong here
Range measures spread between maximum and minimum values, not central tendency, so extreme luxury purchases inflate it directly. It is tempting because it is trivially easy to compute and useful for describing total dispersion in tightly bounded datasets, but it cannot summarise a typical purchase amount.
- ✗
Mean
Why it's wrong here
The mean sums every value, so extreme luxury purchases pull it upward, misrepresenting the typical customer spend. It is tempting because it uses all data points and suits symmetric distributions without outliers; the median, by contrast, depends only on positional rank and resists skew.
- ✗
Mode
Why it's wrong here
The mode is the most frequent value; extreme purchase amounts rarely change which value occurs most often, but it ignores magnitude entirely and is unstable across samples. It is tempting because it resists outliers, and would be correct for categorical data such as preferred product category.
- ✓
Median
Why this is correct
The median depends solely on positional order, so extreme luxury purchase values shift it minimally, unlike the mean, which sums all values and is dragged upward by outliers. It therefore satisfies the requirement for a central tendency measure robust to extreme high values.
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Last reviewed September 2026 · checked against the official CompTIA exam blueprint
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