Prep36 › Guides › ACT Data interpretation practice questions

ACT Data interpretation practice questions

Data interpretation sits in the Statistics & Probability reporting category on the ACT Math section. Prep36 has 11 questions tagged to this skill, every one with a worked explanation. Three of them are below in full, with the reasoning, so you can see what the skill actually looks like before you practise it.

On this page

What Data interpretation covers on the ACT

Within this skill the Prep36 bank covers interpreting the slope of a line of best fit, comparing values in a data set, percent change from a data table, weighted average of two groups, reading and comparing a table and computing a mean from a table.

Math is 45 questions in 50 minutes, which is about 66 seconds each, and it is one of the three sections that average into your composite. The difficulty split across the 11 questions tagged here is 3 easier, 5 medium and 3 harder.

Questions are original, written to the Enhanced ACT format. Prep36 is not affiliated with ACT, Inc.

3 data interpretation questions, with the reasoning

Question 1 easy

A shop tracked units sold across five days: Monday 50, Tuesday 45, Wednesday 30, Thursday 65, and Friday 80. According to the data, how many more units were sold on Friday than on Wednesday?

  1. A. 50 correct
  2. B. 45
  3. C. 15
  4. D. 110
Why: Read the two named values straight from the list and subtract: Friday 80 minus Wednesday 30 equals 50 units. The distractors pull the wrong pair or the wrong operation: 45 is Tuesday's figure copied over, 15 subtracts the two smallest days, and 110 adds Friday and Wednesday instead of finding the difference. Tip: circle exactly the two data points the question names before you compute. Most data-reading errors come from grabbing a neighboring value, not from the arithmetic.
Question 2 medium

A company reported revenue of $50,000 in 2020 and $65,000 in 2021. By what percent did the revenue increase from 2020 to 2021?

  1. A. 15%
  2. B. 23%
  3. C. 30% correct
  4. D. 130%
Why: Percent change divides the increase by the original amount: (65,000 − 50,000) ÷ 50,000 = 15,000 ÷ 50,000 = 0.30, which is 30%. The distractors divide by the wrong base or skip a step: 23% divides the increase by the new value, 15% reads the raw $15,000 change as a percent, and 130% is the ratio of new to old rather than the change. Tip: percent increase is always the change over the original, never over the new figure. Anchoring to the starting value keeps the base correct.
Question 3 hard

In a survey, one group of 10 people reported an average of 80 points and a second group of 15 people reported an average of 90 points. What is the average score of all 25 people combined?

  1. A. 85
  2. B. 86 correct
  3. C. 87
  4. D. 88
Why: A combined average uses totals, not an average of averages: the groups contribute 10 × 80 = 800 and 15 × 90 = 1,350 points, so the overall mean is (800 + 1,350) ÷ 25 = 2,150 ÷ 25 = 86. The distractors ignore the different group sizes: 85 is the simple midpoint of 80 and 90, while 87 and 88 lean toward the larger group by too much. Tip: to blend two averages, rebuild each group's total, sum them, then divide by the full count. The bigger group should pull the mean its way, and totals capture that automatically.

The explanation is the point. Getting a question wrong tells you nothing you did not already suspect; knowing which step you missed is what changes the next one.

Practise the rest of the 11

The other 8 questions on this skill are in the free question bank, filterable by difficulty, each with the same worked explanation. No account and no card.

Open the Math bank

Frequently asked questions

How many ACT data interpretation questions does Prep36 have?
11, each tagged to this skill and each with a worked explanation.
Are these real ACT questions?
No. They are original questions written to the Enhanced ACT format. Prep36 is not affiliated with ACT, Inc.
Is the Math section part of the composite?
Yes. On the Enhanced ACT the composite is the average of English, Math and Reading. Science is optional and reported separately.
Keep readingACT Math practiceEvery Math skill in one place.How many questions can you miss?The miss budget for every score.ACT Score CalculatorTurn raw scores into a composite.
FREE DOWNLOAD

You just read the rule. Here is the version you can keep.

The free Enhanced ACT Cram Kit puts it on one printable page per section, plus a pacing table and a test-day checklist. Your email unlocks the download.

We use your email to send the Cram Kit and occasional ACT prep tips. Unsubscribe anytime. We never sell it or share it.

The whole question bank is free

1,026 original questions and 2 full-length timed tests, free. Every answer explained. No paywall at question 11.

Go to Prep36