ci.pv

Computes adjusted Wald confidence intervals for positive and negative
predictive values (PPV and NPV) of a diagnostic test with retrospective
sampling where the population prevalence rate is assumed to be known. With
retrospective sampling, one random sample is obtained from a subpopulation
that is known to have a "positive" outcome, a second random sample is
obtained from a subpopulation that is known to have a "negative" outcome,
and then the diagnostic test (scored "pass" or "fail") is given in each
sample. PPV and NPV can be expressed as a function of proportion ratios
and the known population prevalence rate (the population proportion who
would "pass"). The confidence intervals for PPV and NPV are based on the
Price-Bonett adjusted Wald confidence interval for a proportion ratio.

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.pv function

<dl><dt>alpha</dt>
<dd>alpha level for 1-alpha confidence</dd>
<dt>f1</dt>
<dd>number of participants with a positive outcome who pass the test</dd>
<dt>f2</dt>
<dd>number of participants with a negative outcome who fail the test</dd>
<dt>n1</dt>
<dd>sample size for the positive outcome group</dd>
<dt>n2</dt>
<dd>sample size for the negative outcome group</dd>
<dt>prev</dt>
<dd>known population proportion with a positive outcome</dd></dl>

Arguments

Confidence intervals for positive and negative predictive values with
retrospective sampling — ci.pv

<dl>

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


<dt>f1</dt>
<dd>number of participants with a positive outcome who pass the test</dd>


<dt>f2</dt>
<dd>number of participants with a negative outcome who fail the test</dd>


<dt>n1</dt>
<dd>sample size for the positive outcome group</dd>


<dt>n2</dt>
<dd>sample size for the negative outcome group</dd>


<dt>prev</dt>
<dd>known population proportion with a positive outcome</dd>

</dl>

ci.pv: Confidence intervals for positive and negative predictive values with retrospective sampling

Description

Usage

Value

Arguments

References

Examples