Panel function for confidence interval

Panel function for confidence interval

panel.ci(x, y, lower, upper, groups = NULL, subscripts, col, fill = if
  (is.null(groups)) plot.line$col else superpose.line$col, alpha = 0.15,
  lty = 0, lwd = if (is.null(groups)) plot.line$lwd else superpose.line$lwd,
  grid = FALSE, ..., col.line = if (is.null(groups)) plot.line$col else
  superpose.line$col)

Arguments

x	variables to be plotted in the scatterplot
y	variables to be plotted in the scatterplot
lower	lower confidence limits
upper	upper confidence limits
groups	an optional grouping variable. If present, panel.superpose will be used instead to display each subgroup
subscripts	see lattice::xyplot()
col	default colours are obtained from plot.symbol and plot.line using trellis.par.get.
fill	other graphical parameters. fill serves the purpose of bg in points for certain values of pch
alpha	opacity for the fill
lty	other graphical parameters. fill serves the purpose of bg in points for certain values of pch
lwd	other graphical parameters. fill serves the purpose of bg in points for certain values of pch
grid	A logical flag, character string, or list specifying whether and how a background grid should be drawn. This provides the same functionality as type="g", but is the preferred alternative as the effect type="g" is conceptually different from that of other type values (which are all data-dependent). Using the grid argument also allows more flexibility. Most generally, grid can be a list of arguments to be supplied to panel.grid, which is called with those arguments. Three shortcuts are available: TRUE: roughly equivalent to list(h = -1, v = -1) "h": roughly equivalent to list(h = -1, v = 0) "v": roughly equivalent to list(h = 0, v = -1) No grid is drawn if grid = FALSE.
...	Extra arguments, if any, for panel.xyplot. In most cases panel.xyplot ignores these. For types "r" and "smooth", these are passed on to panel.lmline and panel.loess respectively.
col.line	default colours are obtained from plot.symbol and plot.line using trellis.par.get.

Examples

mod <- lm(Petal.Width ~ Petal.Length*Species, data = iris)
newdat <- expand.grid(Petal.Length = seq(1, 7, by = 0.1),
                      Species = c("setosa", "versicolor", "virginica"))
pred <- predict(mod, newdat, interval = "confidence")
dd <- cbind(newdat, pred)

xyplot(fit ~ Petal.Length, groups = Species, data = dd,
       prepanel = prepanel.ci, auto.key = list(lines = TRUE, points = FALSE),
       ylab = "Petal Width",
       xlab = "Petal Length",
       lower = dd$lwr, upper = dd$upr, type = "l",
       panel = function(...) {
         panel.ci(..., alpha = 0.15, grid = TRUE)
         panel.xyplot(...)
       })