ci.cv

Computes a confidence interval for a population coefficient of variation
(standard deviation divided by mean). This confidence interval is the
reciprocal of a confidence interval for a standardized mean (see
ci.stdmean). An approximate standard error is recovered
from the confidence interval. The coefficient of variation assumes
ratio-scale scores.

Implements confidence interval and sample size methods that
are especially useful in psychological research. The methods can be
applied in 1-group, 2-group, paired-samples, and multiple-group designs
and to a variety of parameters including means, medians, proportions,
slopes, standardized mean differences, standardized linear contrasts
of means, plus several measures of correlation and association.
Confidence interval and sample size functions are given for single
parameters as well as differences, ratios, and linear contrasts of
parameters. The sample size functions can be used to approximate the
sample size needed to estimate a parameter or function of parameters
with desired confidence interval precision or to perform a variety of
hypothesis tests (directional two-sided, equivalence, superiority,
noninferiority) with desired power. For details see: Statistical Methods
for Psychologists, Volumes 1 – 4, <https://dgbonett.sites.ucsc.edu/>.

Douglas G. Bonett

statpsych

Statistical Methods for Psychologists

Robert J. Calin-Jageman

ci.cv function

<dl><dt>alpha</dt>
<dd>alpha level for 1-alpha confidence</dd>
<dt>m</dt>
<dd>estimated mean</dd>
<dt>sd</dt>
<dd>estimated standard deviation</dd>
<dt>n</dt>
<dd>sample size</dd></dl>

Arguments

Confidence interval for a coefficient of variation — ci.cv

<dl>

<dt>alpha</dt>
<dd>alpha level for 1-alpha confidence</dd>


<dt>m</dt>
<dd>estimated mean</dd>


<dt>sd</dt>
<dd>estimated standard deviation</dd>


<dt>n</dt>
<dd>sample size</dd>

</dl>

ci.cv: Confidence interval for a coefficient of variation

Description

Usage

Value

Arguments

Examples