EVOLUTION-MANAGER
Edit File: corCompSymm.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: Compound Symmetry Correlation Structure</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 corCompSymm {nlme}"><tr><td>corCompSymm {nlme}</td><td style="text-align: right;">R Documentation</td></tr></table> <h2>Compound Symmetry Correlation Structure</h2> <h3>Description</h3> <p>This function is a constructor for the <code>corCompSymm</code> class, representing a compound symmetry structure corresponding to uniform correlation. Objects created using this constructor must later be initialized using the appropriate <code>Initialize</code> method. </p> <h3>Usage</h3> <pre> corCompSymm(value, form, fixed) </pre> <h3>Arguments</h3> <table summary="R argblock"> <tr valign="top"><td><code>value</code></td> <td> <p>the correlation between any two correlated observations. Defaults to 0.</p> </td></tr> <tr valign="top"><td><code>form</code></td> <td> <p>a one sided formula of the form <code>~ t</code>, or <code>~ t | g</code>, specifying a time covariate <code>t</code> and, optionally, a grouping factor <code>g</code>. When a grouping factor is present in <code>form</code>, the correlation structure is assumed to apply only to observations within the same grouping level; observations with different grouping levels are assumed to be uncorrelated. Defaults to <code>~ 1</code>, which corresponds to using the order of the observations in the data as a covariate, and no groups.</p> </td></tr> <tr valign="top"><td><code>fixed</code></td> <td> <p>an optional logical value indicating whether the coefficients should be allowed to vary in the optimization, or kept fixed at their initial value. Defaults to <code>FALSE</code>, in which case the coefficients are allowed to vary.</p> </td></tr> </table> <h3>Value</h3> <p>an object of class <code>corCompSymm</code>, representing a compound symmetry correlation structure. </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>References</h3> <p>Milliken, G. A. and Johnson, D. E. (1992) "Analysis of Messy Data, Volume I: Designed Experiments", Van Nostrand Reinhold. </p> <p>Pinheiro, J.C., and Bates, D.M. (2000) "Mixed-Effects Models in S and S-PLUS", Springer, esp. pp. 233-234. </p> <h3>See Also</h3> <p><code><a href="corClasses.html">corClasses</a></code>, <code><a href="Initialize.corStruct.html">Initialize.corStruct</a></code>, <code><a href="summary.corStruct.html">summary.corStruct</a></code> </p> <h3>Examples</h3> <pre> ## covariate is observation order and grouping factor is Subject cs1 <- corCompSymm(0.5, form = ~ 1 | Subject) # Pinheiro and Bates, pp. 222-225 fm1BW.lme <- lme(weight ~ Time * Diet, BodyWeight, random = ~ Time) # p. 223 fm2BW.lme <- update(fm1BW.lme, weights = varPower()) # p. 225 cs1CompSymm <- corCompSymm(value = 0.3, form = ~ 1 | Subject) cs2CompSymm <- corCompSymm(value = 0.3, form = ~ age | Subject) cs1CompSymm <- Initialize(cs1CompSymm, data = Orthodont) corMatrix(cs1CompSymm) </pre> <hr /><div style="text-align: center;">[Package <em>nlme</em> version 3.1-139 <a href="00Index.html">Index</a>]</div> </body></html>