Range & Standard Deviation
Section: Statistics & ProbabilityBank code: STA-RSDGRE frequency: Medium-HighPro
1. Core Idea
These are measures of spread, not of centre. They answer "how scattered is the data?"
- Range = largest - smallest. Simple, but determined entirely by two values.
- Standard deviation (SD) = the typical distance of a value from the mean. It uses every value.
Good news for GRE students: you almost never have to compute a standard deviation. You need to compare SDs and know how they respond to changes.
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