Default Panel Function for qqmath

This is the default panel function for qqmath.

panel.qqmath(x, f.value = NULL,
             distribution = qnorm,
             qtype = 7,
             groups = NULL, ...,
             tails.n = 0,
             identifier = "qqmath")

Arguments

x

vector (typically numeric, coerced if not) of data values to be used in the panel.

f.value, distribution

Defines how quantiles are calculated. See qqmath for details.

qtype

The type argument to be used in quantile

groups

An optional grouping variable. Within each panel, one Q-Q plot is produced for every level of this grouping variable, differentiated by different graphical parameters.

...

Further arguments, often graphical parameters, eventually passed on to panel.xyplot. Arguments grid and abline of panel.xyplot may be particularly useful.

tails.n

number of data points to represent exactly on each tail of the distribution. This reproduces the effect of f.value = NULL for the extreme data values, while approximating the remaining data. It has no effect if f.value = NULL. If tails.n is given, qtype is forced to be 1.

identifier

A character string that is prepended to the names of grobs that are created by this panel function.

Details

Creates a Q-Q plot of the data and the theoretical distribution given by distribution. Note that most of the arguments controlling the display can be supplied directly to the high-level qqmath call.

Author

Deepayan Sarkar Deepayan.Sarkar@R-project.org

See also

qqmath

Examples

set.seed(0)
xx <- rt(10000, df = 10)
qqmath(~ xx, pch = "+", distribution = qnorm,
       grid = TRUE, abline = c(0, 1),
       xlab.top = c("raw", "ppoints(100)", "tails.n = 50"),
       panel = function(..., f.value) {
           switch(panel.number(),
                  panel.qqmath(..., f.value = NULL),
                  panel.qqmath(..., f.value = ppoints(100)),
                  panel.qqmath(..., f.value = ppoints(100), tails.n = 50))
       }, layout = c(3, 1))[c(1,1,1)]