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Edit File: pairwise.t.test.html
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><title>R: Pairwise t tests</title> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <link rel="stylesheet" type="text/css" href="R.css" /> </head><body> <table width="100%" summary="page for pairwise.t.test {stats}"><tr><td>pairwise.t.test {stats}</td><td style="text-align: right;">R Documentation</td></tr></table> <h2> Pairwise t tests</h2> <h3>Description</h3> <p>Calculate pairwise comparisons between group levels with corrections for multiple testing </p> <h3>Usage</h3> <pre> pairwise.t.test(x, g, p.adjust.method = p.adjust.methods, pool.sd = !paired, paired = FALSE, alternative = c("two.sided", "less", "greater"), ...) </pre> <h3>Arguments</h3> <table summary="R argblock"> <tr valign="top"><td><code>x</code></td> <td> <p> response vector. </p> </td></tr> <tr valign="top"><td><code>g</code></td> <td> <p> grouping vector or factor. </p> </td></tr> <tr valign="top"><td><code>p.adjust.method</code></td> <td> <p> Method for adjusting p values (see <code><a href="p.adjust.html">p.adjust</a></code>). </p> </td></tr> <tr valign="top"><td><code>pool.sd</code></td> <td> <p> switch to allow/disallow the use of a pooled SD </p> </td></tr> <tr valign="top"><td><code>paired</code></td> <td> <p> a logical indicating whether you want paired t-tests. </p> </td></tr> <tr valign="top"><td><code>alternative</code></td> <td> <p> a character string specifying the alternative hypothesis, must be one of <code>"two.sided"</code> (default), <code>"greater"</code> or <code>"less"</code>. Can be abbreviated.</p> </td></tr> <tr valign="top"><td><code>...</code></td> <td> <p> additional arguments to pass to <code>t.test</code>. </p> </td></tr> </table> <h3>Details</h3> <p> The <code>pool.sd</code> switch calculates a common SD for all groups and uses that for all comparisons (this can be useful if some groups are small). This method does not actually call <code>t.test</code>, so extra arguments are ignored. Pooling does not generalize to paired tests so <code>pool.sd</code> and <code>paired</code> cannot both be <code>TRUE</code>. </p> <p>Only the lower triangle of the matrix of possible comparisons is being calculated, so setting <code>alternative</code> to anything other than <code>"two.sided"</code> requires that the levels of <code>g</code> are ordered sensibly. </p> <h3>Value</h3> <p>Object of class <code>"pairwise.htest"</code> </p> <h3>See Also</h3> <p><code><a href="t.test.html">t.test</a></code>, <code><a href="p.adjust.html">p.adjust</a></code></p> <h3>Examples</h3> <pre> attach(airquality) Month <- factor(Month, labels = month.abb[5:9]) pairwise.t.test(Ozone, Month) pairwise.t.test(Ozone, Month, p.adj = "bonf") pairwise.t.test(Ozone, Month, pool.sd = FALSE) detach() </pre> <hr /><div style="text-align: center;">[Package <em>stats</em> version 3.6.0 <a href="00Index.html">Index</a>]</div> </body></html>