Part 4 · Biostatistics and Research Methods
Same concept, other depth: Foundation →
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| Measure | Formula | Pair with | Notes | ||
|---|---|---|---|---|---|
| Range | Max − min | — | Depends on n and extremes | ||
| Interquartile range | Q3 − Q1 | Median | Robust; box plot | ||
| Mean deviation | Σ\ | x − x̄\ | /n | Mean | Rarely used |
| Variance (sample) | s² = Σ(x − x̄)²/(n − 1) | — | Squared units | ||
| Standard deviation | s = √variance | Mean | Same units as data | ||
| Coefficient of variation | CV = SD/mean × 100 | — | Unit‑free; compares variability across measures (and lab precision) |
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