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ACT Science reporting category

ACT Interpretation of Data Practice

Interpretation of Data questions ask you to read tables and graphs, describe trends, estimate values between or beyond data points, and do simple calculations with the numbers shown. According to ACT, this category makes up 38–50% of scored science questions. The core habit is finding the exact row or point a question names.

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38–50% of scored Science questions3 original questionsInstant answer checks

At a glance

Interpretation of Data on the ACT: the key numbers

Section and category facts from ACT.org, checked October 9, 2026. Time per question is ACT's section time divided by its question count.
SectionACT Science: 40 questions in 40 minutes
Scored questions34 scored, 6 field test
Reporting categoryInterpretation of Data
Share of scored questions38–50%, according to ACT
Average time per questionAbout 60 seconds
Counts toward the CompositeNo, Science is optional
Practice on this page3 original questions: Easy, Medium, Hard

What this tests

What does ACT Interpretation of Data test?

Practice questions

Practice ACT Interpretation of Data questions

Pick an answer to check it. Each question has one correct choice.

Question 1 of 3Easy

Dissolved oxygen is oxygen gas mixed into water. Fish and many other aquatic animals take in this oxygen through their gills.

A class placed six open beakers of filtered pond water in water baths set to different temperatures. Students stirred each beaker gently for 30 minutes so the water could exchange gases with the air. They then measured the dissolved oxygen concentration in each beaker with an oxygen probe.

Dissolved oxygen in pond water at six temperatures
Water temperature (°C)Dissolved oxygen (mg/L)
512.6
1011.2
159.9
209.0
258.1
307.5
According to the table, as water temperature increased from 5°C to 30°C, the dissolved oxygen concentration:
Show answer and explanation
Correct answerD. decreased only.

How to solve it

  1. Read the rows in order of temperature: 5°C, 10°C, 15°C, 20°C, 25°C, and 30°C.
  2. The dissolved oxygen values are 12.6, 11.2, 9.9, 9.0, 8.1, and 7.5 mg/L. Each value is lower than the one before it.
  3. A value that falls at every step decreased only, so the answer is D.
Why the other choices miss
A reverses the direction of the trend. B describes a peak, but no value is higher than the one above it. C ignores a total drop of 5.1 mg/L, from 12.6 to 7.5 mg/L, which is large compared with the values themselves.
Question 2 of 3Medium

A student drove up a mountain road one afternoon and stopped at five elevations. At each stop, she held a thermometer in the shade 1.5 m above the ground for 2 minutes and recorded the air temperature.

All five readings were taken within 1 hour under clear skies, so the student assumed the weather did not change while she measured.

Air temperature at five elevations
Elevation (m)Air temperature (°C)
20016.1
60013.7
1,00011.2
1,4008.9
1,8006.4
Based on the table, the air temperature at an elevation of 1,200 m would most likely have been closest to:
Show answer and explanation
Correct answerC. 10.0°C

How to solve it

  1. 1,200 m falls between the 1,000 m row (11.2°C) and the 1,400 m row (8.9°C).
  2. The temperature drops by a similar amount every 400 m, so a straight-line estimate is reasonable.
  3. 1,200 m is halfway between those elevations, so take the halfway temperature: (11.2 + 8.9) / 2 = 10.05°C. The closest choice is 10.0°C, choice C.
Why the other choices miss
A is halfway between the 600 m and 1,000 m readings, so it estimates the temperature at 800 m. B and D are the readings at 1,000 m and 1,400 m. The temperature at 1,200 m should fall between those two values, not equal either one.
Question 3 of 3Hard

Yeast cells break down sugar and release carbon dioxide gas. Students mixed 1 g of dry yeast with 50 mL of a 10% sugar solution in each of four flasks. Each flask was held in a water bath at a different temperature.

A tube carried the gas from each flask into an upside-down graduated cylinder filled with water. Every 2 minutes, students recorded the total volume of gas collected since the start.

Total volume of carbon dioxide collected from each flask
Time (min)Flask at 20°C (mL)Flask at 30°C (mL)Flask at 40°C (mL)Flask at 50°C (mL)
00.00.00.00.0
20.40.81.21.0
41.43.24.62.2
62.65.88.43.0
83.88.612.63.5
Between 2 min and 8 min, which flask had the greatest average rate of gas production, and about what was that rate?
Show answer and explanation
Correct answerA. The 40°C flask; about 1.9 mL/min

How to solve it

  1. Average rate is the gas gained in the interval divided by the time. The interval from 2 min to 8 min is 6 min.
  2. Gas gained: 20°C, 3.8 - 0.4 = 3.4 mL; 30°C, 8.6 - 0.8 = 7.8 mL; 40°C, 12.6 - 1.2 = 11.4 mL; 50°C, 3.5 - 1.0 = 2.5 mL.
  3. The 40°C flask gained the most gas. Its rate is 11.4 mL / 6 min, or 1.9 mL/min, so the answer is A.
Why the other choices miss
B divides the 8-minute total, 12.6 mL, by 6 min instead of using the gain since minute 2. D divides 12.6 mL by 8 min, which is the rate from the start, not from minute 2. C is the correct rate for the 30°C flask, which was slower.

Avoid these traps

What mistakes do students make on Interpretation of Data?

Reading the wrong row

With several similar rows or columns, it is easy to take a value from the line next to the one the question names, especially under time pressure.

Fix: Find the row heading and the column heading the question names, then read the value where they meet.

Skipping the units

Column headings carry units such as mL, L, seconds, or minutes. Comparing numbers without checking units can put an answer off by a factor of 60 or 1,000.

Fix: Read the units in each heading before using a number, and convert before comparing.

Treating totals as rates

When a table lists running totals, the amount gained in an interval is the difference between two rows, not the later value alone.

Fix: Subtract the starting value from the ending value, then divide by the time between them.

Study method

How should you practice ACT Interpretation of Data?

  1. Read the question first, then find the variables it names in the table or graph headings before reading any numbers.
  2. Note the units and the order of the rows or axis values so you know what an increase means.
  3. For trend questions, check the full range of values; one reversal changes the answer.
  4. For estimates, locate the two nearest data points and confirm your answer falls between them or follows the pattern beyond them.
  5. Practice timed table sets in Dolphin, and for each miss, write down the exact row or point you misread.
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FAQ

Questions about ACT Interpretation of Data

How many questions are on the ACT science section?

The science section has 40 questions in 40 minutes. According to ACT, 34 of those questions are scored and 6 are field-test questions that do not count toward your score. That is about 1 minute per question on average.

How much of ACT Science is Interpretation of Data?

According to ACT, Interpretation of Data makes up 38–50% of scored science questions. ACT lists Scientific Investigation at 18–32% and Evaluation of Models and Results at 24–38%, so this category has the highest range of the three.

What should I do when a table uses an unfamiliar science term?

Use the heading and units to work out what the term measures. A column labeled "Dissolved oxygen (mg/L)" is a concentration even if the term is new to you. Answer from the numbers shown, and avoid adding assumptions the passage does not support.

Is there a penalty for wrong answers on ACT Science?

No. ACT does not take points off for incorrect answers, so answer every question. If time runs short, cross out choices that contradict the direction of the trend in the data, then choose from what remains.

How does the ACT report my Interpretation of Data results?

The score report lists each reporting category with questions on your test, along with your number correct and percent correct. Compare this category with the other science categories to decide what to practice next.

Related practice

ACT Scientific Investigation PracticeACT Evaluation of Models and Results PracticeACT Statistics & Probability PracticeAll ACT Science practiceACT English practiceACT Math practiceACT Reading practiceDolphin ACT prepSAT vs ACTCollege ACT score ranges

Sources

Where these facts come from

ACT facts checked . Every practice question on this page is original Dolphin practice written to match one ACT reporting category. None is a released ACT item.

ACT® is a trademark registered by ACT, Inc., which is not affiliated with, and does not endorse, Dolphin.