ci.lc.reg

Computes a confidence interval and test statistic for a linear contrast
of population regression coefficients (e.g., a y-intercept or a slope
coefficient) across groups in a multiple group regression model. Equality
of error variances across groups is not assumed. A Satterthwaite adjustment
to the degrees of freedom is used to improve the accuracy of the confidence
interval.

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.lc.reg function

<dl><dt>alpha</dt>
<dd>alpha level for 1-alpha confidence</dd>
<dt>est</dt>
<dd>vector of parameter estimates</dd>
<dt>se</dt>
<dd>vector of standard errors</dd>
<dt>n</dt>
<dd>vector of group sample sizes</dd>
<dt>s</dt>
<dd>number of predictor variables for each within-group model</dd>
<dt>v</dt>
<dd>vector of contrast coefficients</dd></dl>

Arguments

Confidence interval for a linear contrast of regression coefficients in
multiple group regression model — ci.lc.reg

<dl>

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


<dt>est</dt>
<dd>vector of parameter estimates</dd>


<dt>se</dt>
<dd>vector of standard errors</dd>


<dt>n</dt>
<dd>vector of group sample sizes</dd>


<dt>s</dt>
<dd>number of predictor variables for each within-group model</dd>


<dt>v</dt>
<dd>vector of contrast coefficients</dd>

</dl>

ci.lc.reg: Confidence interval for a linear contrast of regression coefficients in multiple group regression model

Description

Usage

Value

Arguments

Examples