A scientific hypothesis makes a testable prediction or proposes an explanation. Evidence matters when it matches that prediction under relevant conditions and uses an appropriate comparison.
What the SAT is testing
- Command of Evidence
- A supplied claim or point is evaluated with the textual or quantitative evidence that best supports, illustrates, weakens, or challenges it.
Core concept
Write the hypothesis as ‘If X affects Y in this way, then changing or observing X should correspond to Y changing in the predicted direction.’ A treatment/comparison contrast often matters more than either result alone.
Evidence distinctions
Supporting result
Matches the unique prediction. Example: Treatment changes; comparison stays stable
Null result
Predicted difference does not appear. Example: Groups remain nearly equal
Alternative explanation
Another mechanism predicts the same observation. Example: Both hypotheses fit the result
Step-by-step strategy
Claim-first evidence method
- Identify
State the exact claim, including its population, condition, direction, and qualification.
- Predict
Ask what evidence would look like if the claim were true—or what would challenge it.
- Locate
Select only the text or data relevant to that predicted relationship.
- Compare
Evaluate direction, scope, directness, and required assumptions across choices.
- Verify
Check the chosen wording and every cited value against the stimulus.
Visual and data-reading strategy
- Smooth
- Textured
View chart data
| Series | Condition | Temperature retained |
|---|---|---|
| Smooth | Air | 42 |
| Smooth | Liquid | 39 |
| Textured | Air | 61 |
| Textured | Liquid | 40 |
Worked example
Apply 3-9
Scientists hypothesize that a surface texture reduces material cooling specifically by trapping a thin air layer.
Question: Which finding most strongly supports the proposed mechanism?
- Textured samples cooled more slowly in air, but not when submerged in a liquid that displaced trapped air.
- Textured samples were darker than smooth samples.
- Both samples had equal mass before testing.
- Textured samples cooled slowly in both air and liquid.
- Step 1
The mechanism predicts an effect only when trapped air can remain.
- Step 2
Choice A shows the effect in air and its disappearance when air is displaced.
- Step 3
The other options are neutral or less diagnostic of the mechanism.
Why each choice works or fails
- Correct: the condition-specific pattern is uniquely predicted by trapped air.
- Possible confound, not support for the mechanism.
- Control detail, but not an outcome.
- The liquid result makes trapped air less necessary and therefore weakens the mechanism.
Common traps and wrong-answer patterns
Mini check
A hypothesis predicts Treatment > Comparison. The groups score 64 and 65. What does the result most likely do?
- Strongly supports
- May weaken
- Proves causation
- Is irrelevant to the prediction
Show answer and explanation
Answer: B
The predicted difference did not appear, so the null pattern lowers the hypothesis's credibility.
Key takeaways
What to remember
- Translate a hypothesis into a testable prediction.
- Use the relevant treatment or observational comparison.
- Null and contrary findings can weaken a hypothesis.
- Match causal language to what the study design supports.
Put these notes into practice
Apply the ideas with SAT-style questions, then reinforce key details with flashcards.