Plot(x,y) help

Try this code that uses "segments" to draw in the bars

# put data into a nicer form
y=c(1.73,1.30,2.30, 1.83,1.36,2.45,1.46,1.07,2.00,1.58,1.15,2.17)
ym <- matrix(y
    , ncol = 3
    , byrow = TRUE
    , dimnames = list(NULL, c("Val", "Lower", "Upper"))
    )
ym <- cbind(ym, x = 1:4)  # add the x-coord
barWidth <- .1
# plot the data points
plot(ym[, 'x']
    , ym[, 'Val']
    , pch = 19
    , cex = 2
    , ylim = range(ym[, "Upper"], ym[, "Lower"])
    )
# draw the CI values as segments
# three sets of coords - top bar, bottom bar, connecting line
segments(c(ym[, 'x'] - barWidth, ym[, 'x'] - barWidth, ym[, 'x'])
      , c(ym[, 'Upper'], ym[, 'Lower'], ym[, 'Upper'])
      , c(ym[, 'x'] + barWidth, ym[, 'x'] + barWidth, ym[, 'x'])
      , c(ym[, 'Upper'], ym[, 'Lower'], ym[, 'Lower'])
      )

y=c(1.73,1.30,2.30, 1.83,1.36,2.45,1.46,1.07,2.00,1.58,1.15,2.17)

Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.