MeanFromRange: Estimates Mean and Standard Deviation from Median and Range

In SciencesPo: A Tool Set for Analyzing Political Behavior Data

Description

When conductig a meta-analysis study, it is not always possible to recover from reports, the mean and standard deviation values, but rather the median and range of values. This function provides a method for computing the mean and variance estimates from median/range or IQR estimates.

Usage

MeanFromRange(low, med, high, n)

Arguments

low	The min of the data.
med	The median of the data.
high	The max of the data
n	The size of the sample.

Note

One should use these calculations ONLY if there are strong hints, that the overall distribution does not relevantly deviate from normal distribution. The question is then, why some papers report median and IQR if data are not far from normal distribution.

Author(s)

Daniel Marcelino, [e-mail]

References

Hozo, Stela P.; et al (2005) Estimating the mean and variance from the median, range, and the size of a sample. BMC Medical Research Methodology, 5:13.

Examples

# mean=median and SD = IQR/1.35.
# median= 3
# Iqr= 2-3
# median=mean=3
# sd=iqr/1.35 2-3 means 2,5/1.35= sd = 1,85

MeanFromRange(low=5, med=8, high=12, n=10)

SciencesPo documentation built on May 29, 2017, 9:28 p.m.