# VSS.scree

From psych v1.8.12
by William Revelle

##### Plot the successive eigen values for a scree test

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.

- Keywords
- multivariate, hplot

##### Usage

```
scree(rx,factors=TRUE,pc=TRUE,main="Scree plot",hline=NULL,add=FALSE)
VSS.scree(rx, main = "scree plot")
```

##### Arguments

- 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?

##### Details

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`

##### References

##### See Also

##### Examples

```
# NOT RUN {
scree(attitude)
#VSS.scree(cor(attitude)
# }
```

*Documentation reproduced from package psych, version 1.8.12, License: GPL (>= 2)*

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