Quick Answer
The answer is AVERAGE(Sales[Sales]) because this DAX function calculates the arithmetic mean of the Sales column across all rows in the table, directly giving you the average sales per transaction. This works because each row in a properly structured sales table represents a single transaction, so averaging the Sales column inherently computes the average value per transaction. On the Microsoft Power BI Data Analyst PL-300 exam, this question tests your understanding of how AVERAGE differs from aggregation functions like SUM or DIVIDE; a common trap is choosing an option that divides total sales by total quantity, which yields a weighted average per unit rather than per transaction. To remember this, think of the phrase “AVERAGE per row equals average per transaction” — since each row is one transaction, the measure is simply AVERAGE of the sales column.
This PL-300 practice question tests your understanding of model the data. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. 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.
You have a table with columns 'Date', 'Sales', and 'Quantity'. You need to create a measure that calculates the average sales per transaction. Which DAX measure should you use?
AVERAGE(Sales[Quantity])
Why wrong: This averages quantity, not sales.
AVERAGE(Sales[Sales])
AVERAGE calculates the arithmetic mean of the Sales column.
DIVIDE(SUM(Sales[Sales]), SUM(Sales[Quantity]))
Why wrong: This calculates sales per unit, not per transaction.
SUM(Sales[Sales])
Why wrong: This totals sales, not averages.
Answer choices
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
AVERAGE(Sales[Sales])
Option B is correct because AVERAGE of Sales gives average per row. Option A totals sales, not average. Option C averages Quantity, not Sales. Option D divides total sales by total quantity, which is not average per transaction.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
For each option: why learners choose it and why it is or isn't the right answer here.
AVERAGE(Sales[Quantity])
Why it's wrong here
This averages quantity, not sales.
AVERAGE(Sales[Sales])
Why this is correct
AVERAGE calculates the arithmetic mean of the Sales column.
Related concept
Read the scenario before looking for a memorised answer.
DIVIDE(SUM(Sales[Sales]), SUM(Sales[Quantity]))
Why it's wrong here
This calculates sales per unit, not per transaction.
SUM(Sales[Sales])
Why it's wrong here
This totals sales, not averages.
Common exam traps
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
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.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
A cloud solutions architect for a retail company is evaluating services for a new workload. The correct answer here reflects best practice for the specific scenario described — not a general cloud recommendation. Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option. Cloud exam questions reward reading the constraint carefully: the same technology can be right or wrong depending on the use case.
What to study next
Identify which PL-300 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.
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FAQ
Model the data — This question tests Model the data — Read the scenario before looking for a memorised answer..
The correct answer is: AVERAGE(Sales[Sales]) — Option B is correct because AVERAGE of Sales gives average per row. Option A totals sales, not average. Option C averages Quantity, not Sales. Option D divides total sales by total quantity, which is not average per transaction.
Identify which PL-300 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.
Read the scenario before looking for a memorised answer.
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Last reviewed: Jun 21, 2026
This PL-300 practice question is part of Courseiva's free Microsoft 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 PL-300 exam.
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