EVOLUTION-MANAGER
Edit File: mood.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: Mood Two-Sample Test of Scale</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 mood.test {stats}"><tr><td>mood.test {stats}</td><td style="text-align: right;">R Documentation</td></tr></table> <h2>Mood Two-Sample Test of Scale</h2> <h3>Description</h3> <p>Performs Mood's two-sample test for a difference in scale parameters. </p> <h3>Usage</h3> <pre> mood.test(x, ...) ## Default S3 method: mood.test(x, y, alternative = c("two.sided", "less", "greater"), ...) ## S3 method for class 'formula' mood.test(formula, data, subset, na.action, ...) </pre> <h3>Arguments</h3> <table summary="R argblock"> <tr valign="top"><td><code>x, y</code></td> <td> <p>numeric vectors of data values.</p> </td></tr> <tr valign="top"><td><code>alternative</code></td> <td> <p>indicates the alternative hypothesis and must be one of <code>"two.sided"</code> (default), <code>"greater"</code> or <code>"less"</code> all of which can be abbreviated.</p> </td></tr> <tr valign="top"><td><code>formula</code></td> <td> <p>a formula of the form <code>lhs ~ rhs</code> where <code>lhs</code> is a numeric variable giving the data values and <code>rhs</code> a factor with two levels giving the corresponding groups.</p> </td></tr> <tr valign="top"><td><code>data</code></td> <td> <p>an optional matrix or data frame (or similar: see <code><a href="model.frame.html">model.frame</a></code>) containing the variables in the formula <code>formula</code>. By default the variables are taken from <code>environment(formula)</code>.</p> </td></tr> <tr valign="top"><td><code>subset</code></td> <td> <p>an optional vector specifying a subset of observations to be used.</p> </td></tr> <tr valign="top"><td><code>na.action</code></td> <td> <p>a function which indicates what should happen when the data contain <code>NA</code>s. Defaults to <code>getOption("na.action")</code>.</p> </td></tr> <tr valign="top"><td><code>...</code></td> <td> <p>further arguments to be passed to or from methods.</p> </td></tr> </table> <h3>Details</h3> <p>The underlying model is that the two samples are drawn from <i>f(x-l)</i> and <i>f((x-l)/s)/s</i>, respectively, where <i>l</i> is a common location parameter and <i>s</i> is a scale parameter. </p> <p>The null hypothesis is <i>s = 1</i>. </p> <p>There are more useful tests for this problem. </p> <p>In the case of ties, the formulation of Mielke (1967) is employed. </p> <h3>Value</h3> <p>A list with class <code>"htest"</code> containing the following components: </p> <table summary="R valueblock"> <tr valign="top"><td><code>statistic</code></td> <td> <p>the value of the test statistic.</p> </td></tr> <tr valign="top"><td><code>p.value</code></td> <td> <p>the p-value of the test.</p> </td></tr> <tr valign="top"><td><code>alternative</code></td> <td> <p>a character string describing the alternative hypothesis. You can specify just the initial letter.</p> </td></tr> <tr valign="top"><td><code>method</code></td> <td> <p>the character string <code>"Mood two-sample test of scale"</code>.</p> </td></tr> <tr valign="top"><td><code>data.name</code></td> <td> <p>a character string giving the names of the data.</p> </td></tr> </table> <h3>References</h3> <p>William J. Conover (1971), <em>Practical nonparametric statistics</em>. New York: John Wiley & Sons. Pages 234f. </p> <p>Paul W. Mielke, Jr. (1967). Note on some squared rank tests with existing ties. <em>Technometrics</em>, <b>9</b>/2, 312–314. doi: <a href="https://doi.org/10.2307/1266427">10.2307/1266427</a>. </p> <h3>See Also</h3> <p><code><a href="fligner.test.html">fligner.test</a></code> for a rank-based (nonparametric) k-sample test for homogeneity of variances; <code><a href="ansari.test.html">ansari.test</a></code> for another rank-based two-sample test for a difference in scale parameters; <code><a href="var.test.html">var.test</a></code> and <code><a href="bartlett.test.html">bartlett.test</a></code> for parametric tests for the homogeneity in variance. </p> <h3>Examples</h3> <pre> ## Same data as for the Ansari-Bradley test: ## Serum iron determination using Hyland control sera ramsay <- c(111, 107, 100, 99, 102, 106, 109, 108, 104, 99, 101, 96, 97, 102, 107, 113, 116, 113, 110, 98) jung.parekh <- c(107, 108, 106, 98, 105, 103, 110, 105, 104, 100, 96, 108, 103, 104, 114, 114, 113, 108, 106, 99) mood.test(ramsay, jung.parekh) ## Compare this to ansari.test(ramsay, jung.parekh) </pre> <hr /><div style="text-align: center;">[Package <em>stats</em> version 3.6.0 <a href="00Index.html">Index</a>]</div> </body></html>