Plot of the Variances of Derived Variables

DESCRIPTION:

Produces a barplot of the variances of the derived variables.

This function is an S Version 3 generic (see Methods); method functions can be written to handle specific S Version 3 classes of data. Classes that already have methods for this function include bdPrincomp and princomp.

USAGE:

screeplot(object, ...) 
screeplot.princomp(object, variables=<<see below>>, cumulative=T, 
                   main, ...) 
screeplot.bdPrincomp(object, variables=<<see below>>, 
                   cumulative=T, main, ...) 

REQUIRED ARGUMENTS:

object
an object having a class for which screeplot has a method.

OPTIONAL ARGUMENTS:

variables
integer vector telling which variables are to be plotted. The default is to plot the first 10 variables or all the variables if there are less than 10.
cumulative
logical flag: if TRUE, the cumulative fraction of the variance is printed above each bar in the plot.
main
character string giving the title of the plot. The default is the name of object.
...
additional graphics parameters may be given.

VALUE:

invisible vector of the x-coordinates of the centers of the bars.

SIDE EFFECTS:

a plot is produced on the current graphics device.

SEE ALSO:

, . .

EXAMPLES:

longley.pc <- princomp(longley.x, cor=T) 
screeplot(longley.pc)