rootogram {latticeExtra}R Documentation

Trellis Displays of Tukey's Hanging Rootograms

Description

Displays hanging rootograms.

Usage

rootogram(x, ...)

## S3 method for class 'formula':
rootogram(x, data = parent.frame(),
          ylab = expression(sqrt(P(X == x))),
          prepanel = prepanel.rootogram,
          panel = panel.rootogram,
          ...)

prepanel.rootogram(x, y = table(x),
                   dfun = NULL,
                   transformation = sqrt,
                   hang = TRUE,
                   ...)

panel.rootogram(x, y = table(x),
                dfun = NULL,
                col = plot.line$col,
                lty = plot.line$lty,
                lwd = plot.line$lwd,
                alpha = plot.line$alpha,
                transformation = sqrt,
                hang = TRUE,
                ...)

Arguments

x, y For rootogram, x is the object on which method dispatch is carried out. For the "formula" method, x is a formula describing the form of conditioning plot. The formula can be either of the form ~x or of the form y~x. In the first case, x is assumed to be a vector of raw observations, and an observed frequency distribution is computed from it. In the second case, x is assumed to be unique values and y the corresponding frequencies. In either case, further conditioning variables are allowed.
A similar interpretation holds for x and y in prepanel.rootogram and panel.rootogram.
data For the "formula" method, a data frame containing values for any variables in the formula, as well as those in groups and subset if applicable (groups is currently ignored by the default panel function). By default the environment where the function was called from is used.
dfun a probability mass function, to be evaluated at unique x values
prepanel, panel panel and prepanel function used to create the display.
ylab the y-axis label; typically a character string or an expression.
col, lty, lwd, alpha graphical parameters
transformation a vectorized function. Relative frequencies (observed) and theoretical probabilities (dfun) are transformed by this function before being plotted.
hang logical, whether lines representing observed relative freuqncies should “hang” from the curve representing the theoretical probabilities.
... extra arguments, passed on as appropriate. Standard lattice arguments as well as arguments to panel.rootogram can be supplied directly in the high level rootogram call.

Details

This function implements Tukey's hanging rootograms. Also consider the rootogram function in the vcd package, especially if the number of unique values is small.

Value

rootogram produces 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.

Author(s)

Deepayan Sarkar deepayan.sarkar@gmail.com

See Also

xyplot

Examples


library(lattice)

x <- rpois(1000, lambda = 50)

p <- rootogram(~x, dfun = function(x) dpois(x, lambda = 50))
p

lambdav <- c(30, 40, 50, 60, 70)

update(p[rep(1, length(lambdav))],
       aspect = "xy",
       panel = function(x, ...) {
           panel.rootogram(x,
                           dfun = function(x)
                           dpois(x, lambda = lambdav[panel.number()]))
       })

lambdav <- c(46, 48, 50, 52, 54)

update(p[rep(1, length(lambdav))],
       aspect = "xy",
       prepanel = function(x, ...) {
           tmp <-
               lapply(lambdav,
                      function(lambda) {
                          prepanel.rootogram(x,
                                             dfun = function(x)
                                             dpois(x, lambda = lambda))
                      })
           list(xlim = range(sapply(tmp, "[[", "xlim")),
                ylim = range(sapply(tmp, "[[", "ylim")),
                dx = do.call("c", lapply(tmp, "[[", "dx")),
                dy = do.call("c", lapply(tmp, "[[", "dy")))
       },
       panel = function(x, ...) {
           panel.rootogram(x,
                           dfun = function(x)
                           dpois(x, lambda = lambdav[panel.number()]))
           grid::grid.text(bquote(Poisson(lambda == .(foo)),
                                  where = list(foo = lambdav[panel.number()])),
                           y = 0.15,
                           gp = grid::gpar(cex = 1.5))
       },
       xlab = "",
       sub = "Random sample from Poisson(50)")


[Package latticeExtra version 0.4-1 Index]