| % File src/library/stats/man/summary.nls.Rd |
| % Part of the R package, https://www.R-project.org |
| % Copyright 1995-2009 R Core Team |
| % Distributed under GPL 2 or later |
| |
| \name{summary.nls} |
| \alias{summary.nls} |
| \alias{print.summary.nls} |
| \title{Summarizing Non-Linear Least-Squares Model Fits} |
| \description{ |
| \code{summary} method for class \code{"nls"}. |
| } |
| \usage{ |
| \method{summary}{nls}(object, correlation = FALSE, symbolic.cor = FALSE, \dots) |
| |
| \method{print}{summary.nls}(x, digits = max(3, getOption("digits") - 3), |
| symbolic.cor = x$symbolic.cor, |
| signif.stars = getOption("show.signif.stars"), \dots) |
| } |
| \arguments{ |
| \item{object}{an object of class \code{"nls"}.} |
| \item{x}{an object of class \code{"summary.nls"}, usually the result of a |
| call to \code{summary.nls}.} |
| \item{correlation}{logical; if \code{TRUE}, the correlation matrix of |
| the estimated parameters is returned and printed.} |
| \item{digits}{the number of significant digits to use when printing.} |
| \item{symbolic.cor}{logical. If \code{TRUE}, print the correlations in |
| a symbolic form (see \code{\link{symnum}}) rather than as numbers.} |
| \item{signif.stars}{logical. If \code{TRUE}, \sQuote{significance stars} |
| are printed for each coefficient.} |
| \item{\dots}{further arguments passed to or from other methods.} |
| } |
| \details{ |
| The distribution theory used to find the distribution of the |
| standard errors and of the residual standard error (for t ratios) is |
| based on linearization and is approximate, maybe very approximate. |
| |
| \code{print.summary.nls} tries to be smart about formatting the |
| coefficients, standard errors, etc. and additionally gives |
| \sQuote{significance stars} if \code{signif.stars} is \code{TRUE}. |
| |
| Correlations are printed to two decimal places (or symbolically): to |
| see the actual correlations print \code{summary(object)$correlation} |
| directly. |
| } |
| \value{ |
| The function \code{summary.nls} computes and returns a list of summary |
| statistics of the fitted model given in \code{object}, using |
| the component \code{"formula"} from its argument, plus |
| \item{residuals}{the \emph{weighted} residuals, the usual residuals |
| rescaled by the square root of the weights specified in the call to |
| \code{nls}.} |
| \item{coefficients}{a \eqn{p \times 4}{p x 4} matrix with columns for |
| the estimated coefficient, its standard error, t-statistic and |
| corresponding (two-sided) p-value.} |
| \item{sigma}{the square root of the estimated variance of the random |
| error |
| \deqn{\hat\sigma^2 = \frac{1}{n-p}\sum_i{R_i^2},}{\sigma^2 = 1/(n-p) Sum(R[i]^2),} |
| where \eqn{R_i}{R[i]} is the \eqn{i}-th weighted residual.} |
| \item{df}{degrees of freedom, a 2-vector \eqn{(p, n-p)}. (Here and |
| elsewhere \eqn{n} omits observations with zero weights.)} |
| \item{cov.unscaled}{a \eqn{p \times p}{p x p} matrix of (unscaled) |
| covariances of the parameter estimates.} |
| \item{correlation}{the correlation matrix corresponding to the above |
| \code{cov.unscaled}, if \code{correlation = TRUE} is specified and |
| there are a non-zero number of residual degrees of freedom.} |
| \item{symbolic.cor}{(only if \code{correlation} is true.) The value |
| of the argument \code{symbolic.cor}.} |
| } |
| \seealso{ |
| The model fitting function \code{\link{nls}}, \code{\link{summary}}. |
| |
| Function \code{\link{coef}} will extract the matrix of coefficients |
| with standard errors, t-statistics and p-values. |
| } |
| |
| \keyword{regression} |
| \keyword{models} |