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screeplot {stats}

Screeplots
Package: 
stats
Version: 
R 3.0.2

Description

screeplot.default plots the variances against the number of the principal component. This is also the plot method for classes "princomp" and "prcomp".

Usage

 
## S3 method for class 'default':
screeplot((x, npcs = min(10, length(x$sdev)),
          type = c("barplot", "lines"),
          main = deparse(substitute(x)), ...))

Arguments

x
an object containing a sdev component, such as that returned by princomp() and prcomp().
npcs
the number of components to be plotted.
type
the type of plot.
main, ...
graphics parameters.

References

Mardia, K. V., J. T. Kent and J. M. Bibby (1979). Multivariate Analysis, London: Academic Press.

Venables, W. N. and B. D. Ripley (2002). Modern Applied Statistics with S, Springer-Verlag.

See Also

princomp and prcomp.

Examples

require(graphics)
 
## The variances of the variables in the
## USArrests data vary by orders of magnitude, so scaling is appropriate
(pc.cr <- princomp(USArrests, cor = TRUE))  # inappropriate
screeplot(pc.cr)
 
fit <- princomp(covmat = Harman74.cor)
screeplot(fit)
screeplot(fit, npcs = 24, type = "lines")

Documentation reproduced from R 3.0.2. License: GPL-2.