errbar: Add error bars to the plot
In twolodzko/twextras: twextras

Add error bars to the plot

1 2	errbar(low, high, pos = 1:length(low), length = 0.05, horiz = FALSE, add = TRUE, ...)

`low`	vector of lower error margins
`high`	vector of higher error margins
`pos`	vector of locations of bars
`length`	length of error bar whiskers
`horiz`	a logical value. If `FALSE`, the bars are drawn vertically with the first bar to the left. If `TRUE`, the bars are drawn horizontally with the first at the bottom.
`...`	additional `arrows` parameters