VIOLIN: Stata module to generate violin plots

violin produces violin plots, a graphical box plot--kernel density synergism. The violin plot combines the basic summary statistics of a box plot with the visual information provided by a local density estimator. The goal is to reveal the distributional structure in a variable. Much like a traditional box plot, the violin plot displays the median as a short horizontal line, the first-to-third interquartile range as a narrow shaded box, and the lower-to-upper adjacent value range as a vertical line, but it does not plot outside values. Instead, it "boxes" the data with mirrored density curves and labels the y-axis at the minimum, median and maximum observed data values. This is version 1.4.1 of the software. This version has been modified to run correctly under Stata Version 7 (though it remains a version 6 program).