Creating Error Bars in ggplot2

Zhenguo Zhang draws a chart:

Sometimes you may want to create a plot with the following features:

• a point to indicate the mean of a group
• error bars to indicate the standard deviation of the group
• and each group may have subgroups, which are represented by different colors.

In this post, I will show you how to create such a plot using the ggplot2 package in R.

Read on for the demonstration, as well as fixing a common problem of overlapping data points. H/T R-Bloggers.