I'm trying to draw violin plots and wondering if there is an accepted best practice for scaling them across groups. Here are three options I've tried using the R
mtcars data set (Motor Trend Cars from 1973, found here).
Feels right since each plot is a probability plot, and so the area of each should equal 1.0 in some coordinate space. Good for comparing density within each group, but seems more appropriate if the plots are overlaid.
Like equal area, but weighted by number of observations. 6-cyl gets relatively thinner since there are fewer of those cars. Good for comparing density across groups.