size.test.slope

Computes the total sample size required to test a population slope with
desired power in a between-subjects design with a quantitative factor.
In an experimental design, the total sample size would be allocated to the
levels of the quantitative factor and it might be necessary to use a larger
total sample size to achieve equal sample sizes. Set the error 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.test.slope function

<dl><dt>alpha</dt>
<dd>alpha level for hypothesis test</dd>
<dt>pow</dt>
<dd>desired power</dd>
<dt>evar</dt>
<dd>planning value of within-group (error) variance</dd>
<dt>x</dt>
<dd>vector of x values of the quantitative factor</dd>
<dt>slope</dt>
<dd>planning value of slope</dd>
<dt>h</dt>
<dd>null hypothesis value of slope</dd></dl>

Arguments

Sample size for a test of a slope — size.test.slope

<dl>

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


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


<dt>evar</dt>
<dd>planning value of within-group (error) variance</dd>


<dt>x</dt>
<dd>vector of x values of the quantitative factor</dd>


<dt>slope</dt>
<dd>planning value of slope</dd>


<dt>h</dt>
<dd>null hypothesis value of slope</dd>

</dl>

size.test.slope: Sample size for a test of a slope

Description

Usage

Value

Arguments

Examples