size.equiv.mean2

Computes the sample size in each group (assuming equal sample sizes)
required to perform an equivalence test for the difference in population
means with desired power in a 2-group design. The value of h specifies a
range of practical equivalence, -h to h, for the difference in population
means. The planning value for the absolute mean difference must be less
than h. Equivalence tests often require a very large sample size.
Equivalence tests usually use 2 x alpha rather than alpha (e.g., use
alpha = .10 rather alpha = .05). Set the variance planning value to the
largest value within a plausible range for a conservatively large sample
size.

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

size.equiv.mean2 function

<dl><dt>alpha</dt>
<dd>alpha level for hypothesis test</dd>
<dt>pow</dt>
<dd>desired power</dd>
<dt>var</dt>
<dd>planning value of average within-group variance</dd>
<dt>es</dt>
<dd>planning value of mean difference</dd>
<dt>h</dt>
<dd>upper limit for range of practical equivalence</dd></dl>

Arguments

Sample size for a 2-group mean equivalence test — size.equiv.mean2

<dl>

<dt>alpha</dt>
<dd>alpha level for hypothesis test</dd>


<dt>pow</dt>
<dd>desired power</dd>


<dt>var</dt>
<dd>planning value of average within-group variance</dd>


<dt>es</dt>
<dd>planning value of mean difference</dd>


<dt>h</dt>
<dd>upper limit for range of practical equivalence</dd>

</dl>

size.equiv.mean2: Sample size for a 2-group mean equivalence test

Description

Usage

Value

Arguments

Examples