Quantitative and Analytical Reasoning
What this domain tests
Quantitative and Analytical Reasoning asks you to interpret tables, graphs, and short data sets, spot patterns, and draw valid conclusions. It favors ratio, average, percent, probability, and logical-deduction items rather than advanced algebra.
Core rules
- Read the title, axis labels, units, and legend before extracting numbers.
- Average = sum ÷ count; to combine group averages, use total sums, not an average of averages.
- Percent change uses the original value as the base: (new − old) ÷ old.
- A percentage point difference is not the same as a percent difference.
- In sequences, check first differences, then ratios, then alternating rules.
- Correlation does not prove causation; a third variable may explain both.
Worked example
A class of 20 students scores an average of 70. A second class of 30 students scores an average of 80. What is the combined average? Total for class 1 = 20 × 70 = 1,400. Total for class 2 = 30 × 80 = 2,400. Combined total = 3,800; combined count = 50. Average = 3,800 ÷ 50 = 76. Reasoning: the combined average is weighted toward the larger class, so 76 is correct, not the midpoint 75.
Traps
- Averaging the two averages (75) instead of weighting by group size.
- Computing percent change from the new value.
- Reading a graph's height without checking whether the axis starts at zero.
- Assuming a trend will continue indefinitely.
- Confusing 'percent' with 'percentage points.'