pairs.panels: SPLOM, histograms and correlations for a data matrix

Description

Adapted from the help page for pairs, pairs.panels shows a scatter plot of matrices (SPLOM), with bivariate scatter plots below the diagonal, histograms on the diagonal, and the Pearson correlation above the diagonal. Useful for descriptive statistics of small data sets. If lm=TRUE, linear regression fits are shown for both y by x and x by y. Correlation ellipses are also shown.

Usage

pairs.panels(x, smooth = TRUE, scale = FALSE, density=TRUE,ellipses=TRUE,digits = 2, pch = 20,lm=FALSE,  ...)

Arguments

a data.frame or matrix

smooth

TRUE draws loess smooths

scale

TRUE scales the correlation font by the size of the absolute correlation.

density

TRUE shows the density plots as well as histograms

ellipses

TRUE draws correlation ellipses

Plot the linear fit rather than the LOESS smoothed fits.

digits

the number of digits to show

pch

The plot character (defaults to 20 which is a '.').

...

other options for pairs

Value

A scatter plot matrix (SPLOM) is drawn in the graphic window. The lower off diagonal draws scatter plots, the diagonal histograms, the upper off diagonal reports the Pearson correlation (with pairwise deletion).
If lm=TRUE, then the scatter plots are drawn above and below the diagonal, each with a linear regression fit. Useful to show the difference between regression lines.

Details

Shamelessly adapted from the pairs help page. Uses panel.cor, panel.cor.scale, and panel.hist, all taken from the help pages for pairs. Also adapts the ellipse function from John Fox's car package.

pairs.panels is most useful when the number of variables to plot is less than about 6-8. It is particularly useful for an initial overview of the data.

Examples

Run this code

pairs.panels(attitude)   #see the graphics window
data(peas)
pairs.panels(peas,lm=TRUE,xlim=c(14,22),ylim=c(14,22))