ggplot2 Cheat Sheet:
Two Variables: Visualising Error

library(ggplot2)

Cross Bars

df <- data.frame(grp = c("A", "B", "C"), fit = c(5, 7, 6.5), se = c(1, 2, 1))
p <- ggplot(df, aes(grp, fit, ymin = fit - se, ymax = fit + se))
p <- p + geom_crossbar() + ylim(0, 9)
print(p)

Error Bars

df <- data.frame(grp = c("A", "B", "C"), fit = c(5, 7, 6.5), se = c(1, 2, 1))
p <- ggplot(df, aes(grp, fit, ymin = fit - se, ymax = fit + se))
p <- p + geom_errorbar() + ylim(0, 9)
print(p)

Line Range

df <- data.frame(grp = c("A", "B", "C"), fit = c(5, 7, 6.5), se = c(1, 2, 1))
p <- ggplot(df, aes(grp, fit, ymin = fit - se, ymax = fit + se))
p <- p + geom_linerange() + ylim(0, 9)
print(p)

Point Range

df <- data.frame(grp = c("A", "B", "C"), fit = c(5, 7, 6.5), se = c(1, 2, 1))
p <- ggplot(df, aes(grp, fit, ymin = fit - se, ymax = fit + se))
p <- p + geom_pointrange() + ylim(0, 9)
print(p)