7th Grade · Statistics & Probability
Measure of Variability
7.SP.B.4
Definition
Describe how spread out data is. Range = max − min (uses 2 values). MAD = average distance from mean (uses all values). Both measure how much data varies.
Examples
- {4,6,7,8,9,10,12}: range = 12-4 = 8.
- Same data set: MAD = (4+2+1+0+1+2+4)÷7 = 2.
Key rule
Larger range or MAD means more spread out; smaller means more clustered.
Memory hook
Range is quick; MAD uses every point.