plotnScree function

Scree Plot According to a nScree Object Class

Plot a scree plot adding information about a non graphical nScree

analysis.

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

Arguments

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

Returns

Nothing returned.

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)

References

Raiche, G., Walls, T. A., Magis, D., Riopel, M. and Blais, J.-G. (2013). Non-graphical solutions for Cattell's scree test. Methodology, 9(1), 23-29.

See Also

plotuScree, nScree, plotParallel, parallel

Author(s)

Gilles Raiche

Centre sur les Applications des Modeles de Reponses aux Items (CAMRI)

Universite du Quebec a Montreal

raiche.gilles@uqam.ca