ci.ratio.cv2

Computes a confidence interval for a ratio of population coefficients of
variation (CV) in a 2-group design. This confidence interval uses the
confidence interval for each CV and then uses the MOVER-DL method
(see Newcombe, page 138) to obtain a confidence interval for CV1/CV2.
The CV 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.ratio.cv2 function

<dl><dt>alpha</dt>
<dd>alpha level for 1-alpha confidence</dd>
<dt>m1</dt>
<dd>estimated mean for group 1</dd>
<dt>m2</dt>
<dd>estimated mean for group 2</dd>
<dt>sd1</dt>
<dd>estimated standard deviation for group 1</dd>
<dt>sd2</dt>
<dd>estimated standard deviation for group 2</dd>
<dt>n1</dt>
<dd>sample size for group 1</dd>
<dt>n2</dt>
<dd>sample size for group 2</dd></dl>

Arguments

Confidence interval for a ratio of coefficients of variation in a 2-group
design — ci.ratio.cv2

<dl>

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


<dt>m1</dt>
<dd>estimated mean for group 1</dd>


<dt>m2</dt>
<dd>estimated mean for group 2</dd>


<dt>sd1</dt>
<dd>estimated standard deviation for group 1</dd>


<dt>sd2</dt>
<dd>estimated standard deviation for group 2</dd>


<dt>n1</dt>
<dd>sample size for group 1</dd>


<dt>n2</dt>
<dd>sample size for group 2</dd>

</dl>

ci.ratio.cv2: Confidence interval for a ratio of coefficients of variation in a 2-group design

Description

Usage

Value

Arguments

References

Examples