qqmath {lattice}  R Documentation 
QuantileQuantile plot of a sample and a theoretical distribution
qqmath(formula, distribution = qnorm, f.value = NULL, ...)
formula 
formula of the form ~ x  g1 * g2 * ... ,
where x must be a numeric.

distribution 
a quantile function that takes a vector of
probabilities as argument and produces the corresponding
quantiles. Possible values are qnorm , qunif etc.
Distributions with other required arguments need to be passed in as
user defined functions. This is also passed in as an argument to
the panel function (though not used by the default panel function),
and the prepanel function if specified, for use in the commonly
used (pre)panel.qqmathline .

f.value 
optional function of a single integer (representing
sample size), returning a vector of probabilities corresponding to
which quantiles should be plotted. The typical value for this
argument is ppoints , which is also the SPLUS default. If
specified, the probabilities generated by this function is used for
the plotted quantiles, using the quantile function for the
sample, and the distribution argument for the theoretical
distribution.
f.value defaults to NULL , which has the effect of
using ppoints for the quantiles of the theoretical
distribution, but the exact data values for the sample. This is
similar to what happens for qqnorm .

... 
Other arguments 
qqmath
produces a QQ plot of the given sample and a
theoretical distribution. The default behaviour of qqmath
is
different from the corresponding SPLUS function, but is similar to
qqnorm
. See the entry for f.value
for specifics.
This and all other high level Trellis functions have several
arguments in common. These are extensively documented only in the
help page for xyplot
, which should be consulted to learn more
detailed usage.
An object of class ``trellis''. The `update' method can be used to update components of the object and the `print' method (usually called by default) will plot it on an appropriate plotting device.
Deepayan Sarkar Deepayan.Sarkar@Rproject.org
xyplot
, panel.qqmath
,
panel.qqmathline
, prepanel.qqmathline
,
Lattice
, quantile
qqmath(~ rnorm(100), distribution = function(p) qt(p, df = 10)) qqmath(~ height  voice.part, aspect = 1, data = singer, prepanel = prepanel.qqmathline, panel = function(x, y) { panel.qqmathline(y, distribution = qnorm) panel.qqmath(x, y) })