EVOLUTION-MANAGER
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<!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: Check a Design for Balance</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 isBalanced {nlme}"><tr><td>isBalanced {nlme}</td><td style="text-align: right;">R Documentation</td></tr></table> <h2>Check a Design for Balance</h2> <h3>Description</h3> <p>Check the design of the experiment or study for balance. </p> <h3>Usage</h3> <pre> isBalanced(object, countOnly, level) </pre> <h3>Arguments</h3> <table summary="R argblock"> <tr valign="top"><td><code>object</code></td> <td> <p>A <code>groupedData</code> object containing a data frame and a formula that describes the roles of variables in the data frame. The object will have one or more nested grouping factors and a primary covariate.</p> </td></tr> <tr valign="top"><td><code>countOnly</code></td> <td> <p>A logical value indicating if the check for balance should only consider the number of observations at each level of the grouping factor(s). Defaults to <code>FALSE</code>.</p> </td></tr> <tr valign="top"><td><code>level</code></td> <td> <p>an optional integer vector specifying the desired prediction levels. Levels increase from outermost to innermost grouping, with level 0 representing the population (fixed effects) predictions. Defaults to the innermost level.</p> </td></tr> </table> <h3>Details</h3> <p>A design is balanced with respect to the grouping factor(s) if there are the same number of observations at each distinct value of the grouping factor or each combination of distinct levels of the nested grouping factors. If <code>countOnly</code> is <code>FALSE</code> the design is also checked for balance with respect to the primary covariate, which is often the time of the observation. A design is balanced with respect to the grouping factor and the covariate if the number of observations at each distinct level (or combination of levels for nested factors) is constant and the times at which the observations are taken (in general, the values of the primary covariates) also are constant. </p> <h3>Value</h3> <p><code>TRUE</code> or <code>FALSE</code> according to whether the data are balanced or not </p> <h3>Author(s)</h3> <p>José Pinheiro and Douglas Bates <a href="mailto:bates@stat.wisc.edu">bates@stat.wisc.edu</a></p> <h3>See Also</h3> <p><code><a href="../../base/html/table.html">table</a></code>, <code><a href="groupedData.html">groupedData</a></code></p> <h3>Examples</h3> <pre> isBalanced(Orthodont) # should return TRUE isBalanced(Orthodont, countOnly = TRUE) # should return TRUE isBalanced(Pixel) # should return FALSE isBalanced(Pixel, level = 1) # should return FALSE </pre> <hr /><div style="text-align: center;">[Package <em>nlme</em> version 3.1-139 <a href="00Index.html">Index</a>]</div> </body></html>