VSS.scree {psych} | R Documentation |
Cattell's scree test is one of most simple ways of testing the number of components or factors in a correlation matrix. Here we plot the eigen values of a correlation matrix as well as the eigen values of a factor analysis.
scree(rx,factors=TRUE,pc=TRUE,main="Scree plot",hline=NULL,add=FALSE,sqrt=FALSE)
VSS.scree(rx, main = "scree plot",sqrt=FALSE)
rx |
a correlation matrix or a data matrix. If data, then correlations are found using pairwise deletions. |
factors |
If true, draw the scree for factors |
pc |
If true, draw the scree for components |
hline |
if null, draw a horizontal line at 1, otherwise draw it at hline (make negative to not draw it) |
main |
Title |
add |
Should multiple plots be drawn? |
sqrt |
If TRUE, take the sqrt of the eigen value before plotting |
Among the many ways to choose the optimal number of factors is the scree test. A better function to show the scree as well as compare it to randomly parallel solutions is found found in fa.parallel
Following a suggestion from Marco Del Giudice, I added the sqrt option for version 2.2.12. -
William Revelle
https://personality-project.org/r/vss.html
fa.parallel
VSS.plot
, ICLUST
, omega
scree(attitude)
#VSS.scree(cor(attitude)