DA0-002 Data Analysis Practice Question
A data analyst is exploring a dataset of 8,000 customer transactions and notices that the 'transaction_amount' column has a mean of $120 but a median of $45. A small number of transactions exceed $10,000. Which measure of central tendency should the analyst report to describe the typical transaction?
⚠ Common exam trap
The trap here is defaulting to the mean as the summary of a numeric column without checking whether extreme values have distorted it.
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 median, because it is resistant to the influence of extreme values
A large gap between the mean and median signals skew, and here the high-value transactions drag the mean well above the middle of the distribution. The median marks the point where half the transactions are smaller and half larger, so it reflects the typical customer experience far better. For skewed monetary data, the median is the more representative measure of central tendency.
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 range, because it shows the spread between the smallest and largest transactions
Why it's wrong here
The range measures dispersion, not central tendency, and it is entirely determined by the two most extreme values. In this dataset the range would be dominated by the transactions above $10,000, giving no sense of where typical values lie, so it does not answer the question about the typical transaction.
- ✗
The mean, because it uses every value in the dataset
Why it's wrong here
The mean is pulled upward by the extreme high-value transactions, which is why it sits at $120 while most transactions cluster near the median. Reporting the mean would misrepresent the typical transaction for most customers, so it is not the best measure of central tendency in this skewed distribution.
- ✗
The mode, because it identifies the most frequently occurring transaction amount
Why it's wrong here
The mode is useful for categorical data or when a single value repeats often, but transaction amounts are continuous and rarely repeat exactly. It would not summarize the central tendency of a skewed continuous variable, so it is not the appropriate measure to describe the typical transaction.
- ✓
The median, because it is resistant to the influence of extreme values
Why this is correct
The median is the middle value when data is ordered, so a handful of transactions above $10,000 do not shift it. With a mean far above the median, the distribution is right-skewed, and the median better represents the typical transaction amount experienced by most customers.
About these practice questions
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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.