## File: probplot.Rd

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r-cran-e1071 1.7-3-1
 1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677 \name{probplot} \alias{probplot} \alias{lines.probplot} \title{Probability Plot} \description{ Generates a probability plot for a specified theoretical distribution, i.e., basically a \code{\link[stats]{qqplot}} where the y-axis is labeled with probabilities instead of quantiles. The function is mainly intended for teaching the concept of quantile plots. } \usage{ probplot(x, qdist=qnorm, probs=NULL, line=TRUE, xlab=NULL, ylab="Probability in \%", ...) \S3method{lines}{probplot}(x, h=NULL, v=NULL, bend=FALSE, ...) } \arguments{ \item{x}{A data vector for \code{probplot}, an object of class \code{probplot} for the \code{lines} method.} \item{qdist}{A character string or a function for the quantiles of the target distribution.} \item{probs}{Vector of probabilities at which horizontal lines should be drawn.} \item{line}{Add a line passing through the quartiles to the plot?} \item{xlab, ylab}{Graphical parameters.} \item{h}{The y-value for a horizontal line.} \item{v}{The x-value for a vertical line.} \item{bend}{If \code{TRUE}, lines are bent'' at the quartile line, else regular \code{abline}s are added. See examples.} \item{\dots}{Further arguments for \code{qdist} and graphical parameters for lines.} } \author{Friedrich Leisch} \seealso{\code{\link[stats]{qqplot}}} \examples{ ## a simple example x <- rnorm(100, mean=5) probplot(x) ## the same with horizontal tickmarks at the y-axis opar <- par("las") par(las=1) probplot(x) ## this should show the lack of fit at the tails probplot(x, "qunif") ## for increasing degrees of freedom the t-distribution converges to ## normal probplot(x, qt, df=1) probplot(x, qt, df=3) probplot(x, qt, df=10) probplot(x, qt, df=100) ## manually add the line through the quartiles p <- probplot(x, line=FALSE) lines(p, col="green", lty=2, lwd=2) ## Make the line at prob=0.5 red lines(p, h=0.5, col="red") ### The following use the estimted distribution given by the green ### line: ## What is the probability that x is smaller than 7? lines(p, v=7, bend=TRUE, col="blue") ## Median and 90\% confidence interval lines(p, h=.5, col="red", lwd=3, bend=TRUE) lines(p, h=c(.05, .95), col="red", lwd=2, lty=3, bend=TRUE) par(opar) } \keyword{hplot}