EVOLUTION-MANAGER
Edit File: logtrans.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: Estimate log Transformation Parameter</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 logtrans {MASS}"><tr><td>logtrans {MASS}</td><td style="text-align: right;">R Documentation</td></tr></table> <h2> Estimate log Transformation Parameter </h2> <h3>Description</h3> <p>Find and optionally plot the marginal (profile) likelihood for alpha for a transformation model of the form <code>log(y + alpha) ~ x1 + x2 + ...</code>. </p> <h3>Usage</h3> <pre> logtrans(object, ...) ## Default S3 method: logtrans(object, ..., alpha = seq(0.5, 6, by = 0.25) - min(y), plotit = TRUE, interp =, xlab = "alpha", ylab = "log Likelihood") ## S3 method for class 'formula' logtrans(object, data, ...) ## S3 method for class 'lm' logtrans(object, ...) </pre> <h3>Arguments</h3> <table summary="R argblock"> <tr valign="top"><td><code>object</code></td> <td> <p>Fitted linear model object, or formula defining the untransformed model that is <code>y ~ x1 + x2 + ...</code>. The function is generic. </p> </td></tr> <tr valign="top"><td><code>...</code></td> <td> <p>If <code>object</code> is a formula, this argument may specify a data frame as for <code>lm</code>. </p> </td></tr> <tr valign="top"><td><code>alpha</code></td> <td> <p>Set of values for the transformation parameter, alpha. </p> </td></tr> <tr valign="top"><td><code>plotit</code></td> <td> <p>Should plotting be done? </p> </td></tr> <tr valign="top"><td><code>interp</code></td> <td> <p>Should the marginal log-likelihood be interpolated with a spline approximation? (Default is <code>TRUE</code> if plotting is to be done and the number of real points is less than 100.) </p> </td></tr> <tr valign="top"><td><code>xlab</code></td> <td> <p>as for <code>plot</code>. </p> </td></tr> <tr valign="top"><td><code>ylab</code></td> <td> <p>as for <code>plot</code>. </p> </td></tr> <tr valign="top"><td><code>data</code></td> <td> <p>optional <code>data</code> argument for <code>lm</code> fit. </p> </td></tr> </table> <h3>Value</h3> <p>List with components <code>x</code> (for alpha) and <code>y</code> (for the marginal log-likelihood values). </p> <h3>Side Effects</h3> <p>A plot of the marginal log-likelihood is produced, if requested, together with an approximate mle and 95% confidence interval. </p> <h3>References</h3> <p>Venables, W. N. and Ripley, B. D. (2002) <em>Modern Applied Statistics with S.</em> Fourth edition. Springer. </p> <h3>See Also</h3> <p><code><a href="boxcox.html">boxcox</a></code> </p> <h3>Examples</h3> <pre> logtrans(Days ~ Age*Sex*Eth*Lrn, data = quine, alpha = seq(0.75, 6.5, len=20)) </pre> <hr /><div style="text-align: center;">[Package <em>MASS</em> version 7.3-51.4 <a href="00Index.html">Index</a>]</div> </body></html>