ACT Science Data & Graphs: How to Read Tables Fast

ACT says Interpretation of Data makes up roughly 38–50% of current ACT Science.

That makes graphs and tables one of the highest-value Science skills.

You often do not need deep outside science knowledge.

You need to read the data correctly. For more Science strategy like this, browse the rest of our ACT guides.

Step 1: read the axes

Before interpreting a graph, identify:

• x-axis;
• y-axis;
• units;
• legend;
• scale.

A graph can look dramatic simply because the y-axis has a narrow range.

Step 2: identify the trend

Ask:

As x increases, does y:

• increase?
• decrease?
• stay roughly constant?
• rise then fall?

Do not calculate unless needed.

Interpolation

Estimate inside the observed range.

If:

20°C → 10 units
30°C → 20 units

A value at 25°C might reasonably be around the middle if the relationship appears linear.

Extrapolation

Estimate outside the observed range.

This is less certain.

ACT may ask which prediction best follows the trend.

Do not assume a trend continues forever unless the question asks you to extend it.

Compare groups

Suppose a graph shows:

• Treatment A;
• Treatment B.

At time 5:

A = 18
B = 12

Difference:

[ 18-12=6 ]

Always compare at the same x-value unless asked otherwise.

Watch units

Common traps:

• seconds vs minutes;
• grams vs kilograms;
• percentages vs raw counts;
• °C vs °F.

Table strategy

Do not read every cell.

Use the question to identify:

• correct row;
• correct column;
• required comparison.

For the broader approach to every ACT Science question type, see our ACT Science strategy guide.

Original practice

Table:

1

At which temperature is growth rate highest?

2

Between which temperatures does growth rate decrease?

3

From 10°C to 30°C, how much does growth rate increase?

Answers

1. 30°C
2. 30°C to 40°C
3. 7

Conflicting viewpoints

Graphs may also support or weaken a scientist's claim.

If Scientist 1 predicts:

output rises as temperature rises

but the graph falls after 30°C, the data do not fully support the claim across the entire range.

No calculator

Calculators are not allowed on ACT Science.

Most arithmetic is intentionally manageable without one. If you are still deciding whether to include this optional section on test day, our guide on whether to take ACT Science walks through the trade-offs.

Fast checklist

1. What does x mean?
2. What does y mean?
3. Units?
4. Which dataset?
5. Trend?
6. Exact value or estimate?
7. Does the answer overstate the data?

See our complete guide to the Enhanced ACT for how Science fits into the rest of the test.

Official source

• ACT Science Test Description: https://www.act.org/content/act/en/products-and-services/the-act/test-preparation/description-of-science-test.html

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