# plotnScree: Scree Plot According to a nScree Object Class In nFactors: Parallel Analysis and Other Non Graphical Solutions to the Cattell Scree Test

## Description

Plot a scree plot adding information about a non graphical `nScree` analysis.

## Usage

 ```1 2``` ```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"```)

## Value

Nothing returned.

## Author(s)

Gilles Raiche
Centre sur les Applications des Modeles de Reponses aux Items (CAMRI)
Universite du Quebec a Montreal
raiche.gilles@uqam.ca

## 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.

`plotuScree`, `nScree`, `plotParallel`, `parallel`
 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26``` ```## 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) ```