dispersion(x,y,ulim,llim=ulim,arrow.cap=0.01,arrow.gap=NA,type="a",...)
dispbars(x,y,ulim,llim=ulim,arrow.cap=0.01,arrow.gap=NA,...)arrows or lines
depending upon type.dispersion displays a measure of dispersion on an existing plot.
Currently it will display either vertical lines with caps (error bars) or lines
that form an "confidence band" around a line of central tendency.
dispbars is now a call to dispersion with type set to
a.
If arrow.gap is greater than or equal to the upper or lower
limit for a bar, segments is used to draw the upper and
lower caps with no bars to avoid zero length arrows.arrows, segments, code{lines}