addErrorBars: Add error bars to a barplot.
Description
This function adds error bars to an existing barplot.
Usage
addErrorBars(means, errors, two.side = FALSE)
Arguments
  
- means
 
vector of means plotted in the barplot
  
- errors
 
vector of standard errors (signle positive values) to be plotted.
  
- two.side
 
should the error bars be two-sided?
Author
Steve Horvath and Peter Langfelder