SAT Math: Interpreting Standard Deviation
20+ practice questions in Praczo
The concept, explained
- 1
Standard deviation (SD) measures how spread out data values are around the mean. A larger SD = more spread; smaller SD = more clustered.
- 2
The SAT never asks you to calculate SD — it only asks you to compare or interpret it.
- 3
If two datasets have the same mean but different SDs, the one with the higher SD has more variability.
- 4
Adding or removing a value far from the mean increases SD; adding one near the mean decreases it.
- 5
A dataset where all values are equal has SD = 0.
- ✗ Confusing standard deviation with range. Two datasets can have the same range but very different SDs depending on how values cluster.
- ✗ Thinking a higher mean implies a higher SD — they are independent measures.
SAT-style practice
Dataset A: {10, 10, 10, 10, 10}. Dataset B: {2, 6, 10, 14, 18}. Both have mean 10. Which has the greater standard deviation?
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