Q-Q Diagram Confidence Intervals Panels

Panel function to go along with lattice::qqmath() and lattice::panel.qqmathline(). Adds filled confidence bands to the Q-Q-plot.

panel.qqmathci(x, y = x, distribution = qnorm, probs = c(0.25, 0.75),
  qtype = 7, groups = NULL, ci = 0.95, alpha = 0.25,
  col = trellis.par.get("plot.line")$col, ..., col.line)

Arguments

x	The original sample, possibly reduced to a fewer number of quantiles, as determined by the f.value argument to qqmath
y	an alias for x for backwards compatibility
distribution	quantile function for reference theoretical distribution.
probs	numeric vector of length two, representing probabilities. Corresponding quantile pairs define the line drawn.
qtype	the type of quantile computation used in quantile
groups	optional grouping variable. If non-null, a line will be drawn for each group.
ci	Confidence level
alpha	Alpha level for the color fill
col	Color fill for the confidence bands.
…	Arguments passed to lattice::panel.superpose() and lattice::panel.polygon()
col.line	Color fill for the confidence bands. Is used internally by lattice::panel.superpose() and should generally not be changed.

Value

Augments a trellis plot panel, such as that created by lattice::qqmath(), with confidence levels.

Details

The function tries to figure out the density function counterpart to that provided in the argument distribution by regular expressions.

See also

lattice::panel.qqmathline(), lattice::qqmath(), and lattice::panel.qqmath().

Examples

qqmath(~ height | voice.part, aspect = "xy", data = singer,
       prepanel = prepanel.qqmathline,
       panel = function(x, ...) {
         panel.qqmathci(x, ...)
         panel.qqmathline(x, ...)
         panel.qqmath(x, ...)
       })