7th Grade · Statistics & Probability
Informal Comparative Inference
7.SP.B.4
Definition
Using visual comparisons of center (mean/median) and variability (range/MAD) of two distributions to draw conclusions about the populations they represent.
Examples
- Class A mean 80 vs Class B mean 70 — a 10-point difference, about 2× the MAD, suggesting a meaningful gap.
- Compare centers, spreads, and overlap between the two groups.
Key rule
Compare centers, then spreads, then overlap, before stating a conclusion.
Memory hook
Compare the middle, the spread, and how much they overlap.