relrisk

Performs power and sample size calculations for a test of relative risk, p2/p1.
Can solve for power, N1, n.ratio or alpha.

Power and sample size calculations for a variety of study designs and
outcomes. Methods include t tests, ANOVA (including tests for interactions,
simple effects and contrasts), proportions, categorical data (chi-square tests
and proportional odds), linear, logistic and Poisson regression, alternative
and coprimary endpoints, power for confidence intervals, correlation
coefficient tests, cluster randomized trials, individually randomized group
treatment trials, multisite trials, treatment-by-covariate interaction effects
and nonparametric tests of location. Utilities are provided for
computing various effect sizes. Companion package to the book
"Power and Sample Size in R", Crespi (2025, ISBN:9781138591622).
Further resources available at <https://powerandsamplesize.org/>.

Catherine M. Crespi

powertools

Power and Sample Size Tools

Zichen Liu

Kristen M. McGreevy

relrisk function

<dl><dt>n1</dt>
<dd>The sample size for group 1.</dd>
<dt>n.ratio</dt>
<dd>The ratio n2/n1 between the sample sizes of two groups; defaults to 1 (equal group sizes).</dd>
<dt>p1</dt>
<dd>The proportion in group 1.</dd>
<dt>p2</dt>
<dd>The proportion in group 2.</dd>
<dt>RR0</dt>
<dd>The relative risk under the null (p2/p1); defaults to 1.</dd>
<dt>alpha</dt>
<dd>The significance level (type 1 error rate); defaults to 0.05.</dd>
<dt>power</dt>
<dd>The specified level of power.</dd>
<dt>sides</dt>
<dd>Either 1 or 2 (default) to specify a one- or two- sided hypothesis test.</dd>
<dt>v</dt>
<dd>Either TRUE for verbose output or FALSE (default) to output computed argument only.</dd></dl>

Arguments

Power calculation for relative risk — relrisk

<dl>

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


<dt>n.ratio</dt>
<dd>The ratio n2/n1 between the sample sizes of two groups; defaults to 1 (equal group sizes).</dd>


<dt>p1</dt>
<dd>The proportion in group 1.</dd>


<dt>p2</dt>
<dd>The proportion in group 2.</dd>


<dt>RR0</dt>
<dd>The relative risk under the null (p2/p1); defaults to 1.</dd>


<dt>alpha</dt>
<dd>The significance level (type 1 error rate); defaults to 0.05.</dd>


<dt>power</dt>
<dd>The specified level of power.</dd>


<dt>sides</dt>
<dd>Either 1 or 2 (default) to specify a one- or two- sided hypothesis test.</dd>


<dt>v</dt>
<dd>Either TRUE for verbose output or FALSE (default) to output computed argument only.</dd>

</dl>

relrisk: Power calculation for relative risk

Description

Usage

Value

Arguments

Examples