The correct answer is to replace nulls with the median income per region. This strategy is most appropriate because income data is often geographically skewed; imputing with the median per region preserves the local central tendency while avoiding the distortion that a global mean would introduce from high- or low-income areas. On the CompTIA AI+ AI0-001 exam, this question tests your understanding of domain-aware imputation—specifically, how to handle missing values in structured data without introducing bias or reducing sample size. A common trap is choosing the overall mean, which ignores regional variance, or simply dropping rows, which weakens the dataset. Remember the memory tip: “Median by group, not mean by whole”—when a column’s values naturally cluster by a categorical feature, always impute within those groups to maintain data integrity.
AI0-001 AI Models and Data Engineering Practice Question
This AI0-001 practice question tests your understanding of ai models and data engineering. Compare every option against the stated constraints before choosing — the best answer satisfies all requirements, not just the most obvious one. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
Refer to the exhibit. A data engineer runs a validation report on the customers table. The "income" column has 12 null values. Which imputation strategy is most appropriate for this column?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Replace nulls with the median income per region
Income varies by region, so imputing with the median per region accounts for regional differences. The mean of entire dataset may be skewed, 0 is inappropriate, and removing rows reduces sample size.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
✗
Remove rows with null income
Why it's wrong here
Removing 12 rows may lose data, especially if missingness is not random.
✓
Replace nulls with the median income per region
Why this is correct
Median per region respects regional variation and is robust to outliers.
Related concept
Read the scenario before looking for a memorised answer.
✗
Replace nulls with 0
Why it's wrong here
Zero income is unrealistic and would introduce bias.
✗
Replace nulls with the mean income of the entire dataset
Why it's wrong here
Mean may be affected by regional differences and outliers.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
Read the scenario before looking for a memorised answer.
Find the constraint that changes the correct option.
Eliminate answers that are true in general but not in this case.
Use explanations to understand the rule behind the answer.
TExam Day Tips
→Underline the problem statement mentally.
→Watch for words such as best, first, most likely and least administrative effort.
→Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A practitioner preparing for the AI0-001 exam encounters this exact type of scenario on the job. The correct answer here is not the most general option — it is the best answer for the specific constraint described. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Real exam questions reward reading the full scenario before eliminating options, because the constraint defines which answer fits.
What to study next
Got this wrong? Here's your next step.
Identify which AI0-001 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
AI Models and Data Engineering — This question tests AI Models and Data Engineering — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Replace nulls with the median income per region — Income varies by region, so imputing with the median per region accounts for regional differences. The mean of entire dataset may be skewed, 0 is inappropriate, and removing rows reduces sample size.
What should I do if I get this AI0-001 question wrong?
Identify which AI0-001 exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
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Question Discussion
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