Data Analysis questions test careful reading as much as computation. Titles, axes, units, legends, scales, and comparison groups determine what a displayed value means and what conclusions are justified.
Essential concepts
\[ ext{relative change}= rac{ ext{new}- ext{old}}{ ext{old}}\]
Multiply by 100% when the question requests a percent change.
SAT strategy and application
Calculate change from displayed values
A chart shows that monthly ridership increased from 120 thousand to 150 thousand. What was the percent increase?
- Find the change
\(150-120=30\) thousand.
- Divide by the original
\(30/120=0.25\).
Percent increase: 25%.
Mistakes and traps
Check your understanding
A survey response rate rises from 40% to 46%. By how many percentage points did it rise?
- 6
- 15
- 40
- 46
Show answer and explanation
Answer: 6 percentage points
Percentage-point change is the direct difference: 46 − 40 = 6.
Key takeaways
What to remember
- Read titles, axes, units, legends, and scales before calculating.
- Identify the exact groups and values the question compares.
- Separate percentage points from relative percent change.
- Do not infer causation from association alone.
Continue learning
Put these notes into practice
Apply the ideas with SAT-style questions, then reinforce key details with flashcards.