ci.mean2

Computes equal variance and unequal variance confidence intervals for a
population 2-group mean difference using the estimated means, estimated
standard deviations, and sample sizes. Also computes equal variance and
unequal variance independent-samples t-tests. Use the t.test function for
raw data input.

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.mean2 function

<dl><dt>alpha</dt>
<dd>alpha level for 1-alpha confidence</dd>
<dt>m1</dt>
<dd>estimated mean for group 1</dd>
<dt>m2</dt>
<dd>estimated mean for group 2</dd>
<dt>sd1</dt>
<dd>estimated standard deviation for group 1</dd>
<dt>sd2</dt>
<dd>estimated standard deviation for group 2</dd>
<dt>n1</dt>
<dd>sample size for group 1</dd>
<dt>n2</dt>
<dd>sample size for group 2</dd></dl>

Arguments

Confidence interval for a 2-group mean difference — ci.mean2

<dl>

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


<dt>m1</dt>
<dd>estimated mean for group 1</dd>


<dt>m2</dt>
<dd>estimated mean for group 2</dd>


<dt>sd1</dt>
<dd>estimated standard deviation for group 1</dd>


<dt>sd2</dt>
<dd>estimated standard deviation for group 2</dd>


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


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

</dl>

ci.mean2: Confidence interval for a 2-group mean difference

Description

Usage

Value

Arguments

References

Examples