# biplot.princomp

##### Biplot for Principal Components

Produces a biplot (in the strict sense) from the output of
`princomp`

or `prcomp`

- Keywords
- multivariate, hplot

##### Usage

```
# S3 method for prcomp
biplot(x, choices = 1:2, scale = 1, pc.biplot = FALSE, …)
```# S3 method for princomp
biplot(x, choices = 1:2, scale = 1, pc.biplot = FALSE, …)

##### Arguments

- x
an object of class

`"princomp"`

.- choices
length 2 vector specifying the components to plot. Only the default is a biplot in the strict sense.

- scale
The variables are scaled by

`lambda ^ scale`

and the observations are scaled by`lambda ^ (1-scale)`

where`lambda`

are the singular values as computed by`princomp`

. Normally`0 <= scale <= 1`

, and a warning will be issued if the specified`scale`

is outside this range.- pc.biplot
If true, use what Gabriel (1971) refers to as a "principal component biplot", with

`lambda = 1`

and observations scaled up by sqrt(n) and variables scaled down by sqrt(n). Then inner products between variables approximate covariances and distances between observations approximate Mahalanobis distance.- …
optional arguments to be passed to

`biplot.default`

.

##### Details

This is a method for the generic function `biplot`

. There is
considerable confusion over the precise definitions: those of the
original paper, Gabriel (1971), are followed here. Gabriel and
Odoroff (1990) use the same definitions, but their plots actually
correspond to `pc.biplot = TRUE`

.

##### Side Effects

a plot is produced on the current graphics device.

##### References

Gabriel, K. R. (1971).
The biplot graphical display of matrices with applications to
principal component analysis.
*Biometrika*, **58**, 453--467.
10.2307/2334381.

Gabriel, K. R. and Odoroff, C. L. (1990).
Biplots in biomedical research.
*Statistics in Medicine*, **9**, 469--485.
10.1002/sim.4780090502.

##### See Also

##### Examples

`library(stats)`

```
# NOT RUN {
require(graphics)
biplot(princomp(USArrests))
# }
```

*Documentation reproduced from package stats, version 3.5.0, License: Part of R 3.5.0*