size.ci.pbcor

Computes the sample size required to estimate a population point-biserial
correlation with desired confidence interval precision in a two-group
nonexperimental design with simple random sampling. A two-group
nonexperimental design implies two subpopulations (e.g., all boys and all
girls in a school district). This function requires a planning value for the
proportion of population members who belong to one of the two subpopulations.
Set the correlation planning value to the smallest absolute 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.ci.pbcor function

<dl><dt>alpha</dt>
<dd>alpha level for 1-alpha confidence</dd>
<dt>cor</dt>
<dd>planning value of point-biserial correlation</dd>
<dt>w</dt>
<dd>desired confidence interval width</dd>
<dt>p</dt>
<dd>proportion of members in one of the two subpopulations</dd></dl>

Arguments

Sample size for a point-biserial correlation confidence interval — size.ci.pbcor

<dl>

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


<dt>cor</dt>
<dd>planning value of point-biserial correlation</dd>


<dt>w</dt>
<dd>desired confidence interval width</dd>


<dt>p</dt>
<dd>proportion of members in one of the two subpopulations</dd>

</dl>

size.ci.pbcor: Sample size for a point-biserial correlation confidence interval

Description

Usage

Value

Arguments

References

Examples