power.prop2

Computes the approximate power for a test of equal population proportions
in a 2-group design for the planned sample sizes. This function requires
planning values for both proportions. Set the proportion planning values
to .5 for a conservatively low power estimate. The planning value for the
proportion difference could be set to the difference of the two proportion
planning values or it could be set to a minimally interesting effect 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

power.prop2 function

<dl><dt>alpha</dt>
<dd>alpha level for hypothesis test</dd>
<dt>n1</dt>
<dd>planned sample size for group 1</dd>
<dt>n2</dt>
<dd>planned sample size for group 2</dd>
<dt>p1</dt>
<dd>planning value of proportion for group 1</dd>
<dt>p2</dt>
<dd>planning value of proportion for group 2</dd>
<dt>es</dt>
<dd>planning value of proportion difference</dd></dl>

Arguments

Approximates the power of a 2-group proportion test for planned sample
sizes — power.prop2

<dl>

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


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


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


<dt>p1</dt>
<dd>planning value of proportion for group 1</dd>


<dt>p2</dt>
<dd>planning value of proportion for group 2</dd>


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

</dl>

power.prop2: Approximates the power of a 2-group proportion test for planned sample sizes

Description

Usage

Value

Arguments

Examples