Chapter 14 Means and Confidence Intervals

With plotmeans() function from gplots package

#install.packages("gplots")
library(gplots)

## 
## Attaching package: 'gplots'

## The following object is masked from 'package:stats':
## 
##     lowess

# Plot the mean of teeth length by dose groups
plotmeans(len ~ dose, data = ToothGrowth, frame = FALSE)

## Warning in plot.xy(xy.coords(x, y), type = type, ...): "frame" is not a
## graphical parameter

## Warning in axis(1, at = 1:length(means), labels = legends, ...): "frame" is
## not a graphical parameter

## Warning in plot.xy(xy.coords(x, y), type = type, ...): "frame" is not a
## graphical parameter