\name{plotnScree}

\alias{plotnScree}

\title{ Scree Plot According to a nScree Object Class }

\description{
Plot a scree plot adding information about a non graphical \code{nScree} analysis.
}

\usage{
plotnScree(nScree,
legend = TRUE,
ylab   = "Eigenvalues",
xlab   = "Components",
main   = "Non Graphical Solutions to Scree Test"
)
}

\arguments{
\item{nScree}{  Results of a previous \code{nScree} analysis }
\item{legend}{  Logical indicator of the presence or not of a legend  }
\item{xlab}{    Label of the x axis (default to \code{"Component"}) }
\item{ylab}{    Label of the y axis (default to \code{"Eigenvalue"}) }
\item{main}{    Main title (default to \code{"Non Graphical Solutions to the Scree Test"}) }
}

\value{
Nothing returned.
}

\references{
Raiche, G., Riopel, M. and Blais, J.-G. (2006). \emph{Non graphical solutions for the Cattell's scree test}.
Paper presented at the International Annual meeting of the Psychometric Society, Montreal.
[\url{http://www.er.uqam.ca/nobel/r17165/RECHERCHE/COMMUNICATIONS/}]
}

\author{
Gilles Raiche \cr
Centre sur les Applications des Modeles de Reponses aux Items (CAMRI) \cr
Universite du Quebec a Montreal\cr
\email{raiche.gilles@uqam.ca}, \url{http://www.er.uqam.ca/nobel/r17165/}
}

\seealso{
}

\examples{
## INITIALISATION
data(dFactors)                      # Load the nFactors dataset
attach(dFactors)
vect         <- Raiche              # Use the second example from Buja and Eyuboglu
# (1992, p. 519, nsubjects not specified by them)
eigenvalues  <- vect$eigenvalues # Extract the observed eigenvalues nsubjects <- vect$nsubjects      # Extract the number of subjects
variables    <- length(eigenvalues) # Compute the number of variables
rep          <- 100                 # Number of replications for the parallel analysis
cent         <- 0.95                # Centile value of the parallel analysis

## PARALLEL ANALYSIS (qevpea for the centile criterion, mevpea for the mean criterion)
aparallel    <- parallel(var     = variables,
subject = nsubjects,
rep     = rep,
cent    = cent)$eigen$qevpea  # The 95 centile

## NOMBER OF FACTORS RETAINED ACCORDING TO DIFFERENT RULES
results <- nScree(eig       = eigenvalues,
aparallel = aparallel
)

results

## PLOT ACCORDING TO THE nScree CLASS
plotnScree(results)
}

\keyword{ Graphics }