*! version 1.0.0 21Aug2023

Title

cvequal -- Equality of coefficients of variation (CV) from k populations

Syntax

cvequal
varname
[if] [in]
, by(groupvar)

Description

cvequal tests the hypothesis that the coefficients of variation (CV) are the same for k populations, with unequal sample sizes (Feltz & Miller 1996).
This statistic is invariant under the choice of the order of the populations, and is asymptotically chi2. (Feltz & Miller 1996).

Options

by(groupvar) is required. It specifies a variable that identifies the groups.

Example

Setup

. sysuse census

Test equality of the coefficient of variation for the median age across all regions simultaneously

. cvequal medage, by(region)

Stored results

cvequal stores the following in r():

Scalars

r(df) degrees of freedom

r(chi2) chi-squared

r(pval) p-value for the chi-squared distribution

References

Feltz, C. J., & G. E. Miller. 1996. An asymptotic test for the equality of coefficients of variation (CV) from k populations. Statistics in Medicine 15: 647-658.

Citation of cvequal

cvequal is not an official Stata command. It is a free contribution
to the research community, like a paper. Please cite it as such:

Linden A. (2023). CVEQUAL: Stata module to compute the equality of coefficients of variation (CV) from k populations.

Authors

Ariel Linden

President, Linden Consulting Group, LLC

alinden@lindenconsulting.org

Also see

Online: wscv (if installed)