Median to Mean Conversion
Converts median-based summary statistics into estimated mean and standard deviation — invaluable when a paper reports median (with quartiles or range) but your meta-analysis needs mean and SD.
Inputs
- Sample size (n)
- Median
- Either Q1 and Q3 (quartiles), or Min and Max
Methods used (Hozo et al., 2005)
| Available data | Mean estimate | SD estimate |
|---|---|---|
| Median + Q1 + Q3 | (Q1 + median + Q3) / 3 |
(Q3 - Q1) / 1.35 |
| Median + Min + Max | Hozo formula based on min, median, max, and n | Hozo range-based SD formula |
The (Q3 - Q1) / 1.35 approximation comes from the fact that for a normal distribution, the IQR is approximately 1.35 standard deviations.
These estimates assume approximate normality; for highly skewed data they are less accurate.
A UniversalChatBot is available for discussion.