create a boxplot in R that labels a box with the sample size (N)

Question

Is there a way to create a boxplot in R that will display with the box (somewhere) an \"N=(sample size)\"? The varwidth logical adjusts the width of the box on the basis of sam

Answer 1

To get the n on top of the bar, you could use text with the stat details provided by boxplot as follows

b <- boxplot(xvar ~ f1, data=frame, plot=0)
text(1:length(b$n), b$stats[5,]+1, paste("n=", b$n))

The stats field of b is a matrix, each column contains the extreme of the lower whisker, the lower hinge, the median, the upper hinge and the extreme of the upper whisker for one group/plot.