Lattice panel function for confidence intervals with capped bars

This panel function is defined to plot confidence intervals in a multi-panel lattice display where the x-variable is categorical. Note, both lower and upper must be passed directly to xyplot as they will be passed down to the panel function.

panel.2cat(x, y, subscripts, lower, upper, length = 0.2)

Arguments

x, y	Data from the call to xyplot.
subscripts	Variable used to created the juxtaposed panels.
lower, upper	95% lower and upper bounds of y.
length	Length of the arrow head lines.

Examples

library(lattice)
library(effects)
data(Duncan, package="carData")
Duncan$inc.cat <- cut(Duncan$income, 3)
mod <- lm(prestige~ inc.cat * type + education,
  data=Duncan)
e1 <- effect("inc.cat*type", mod)
update(plot(e1), panel=panel.2cat)