This command allows two options. SMOOTH enables you to
set a smoothing parameter. When you do an actual histogram, the equivalent of
a smoothing parameter is the number of categories into which to group the
districts. For kernel density estimates, the smoothing parameter is a slightly
more technical consideration; all you really need to remember is that the
higher the number, the more smoothing, just as with a histogram. If you smooth
too little, you will only reproduce the data and HIST will not help in
interpretation. If you smooth too much, you may lose some smaller patterns,
such as a clump of a few districts far from the mean of the others. Since HIST
is a diagnostic tool, the best thing to do is to use the smoothing value
automatically generated by JudgeIt in the first run. JudgeIt will print the
smoothing parameter it chose for your particular problem after drawing the
graph. Then you may decide to increase or decrease the smoothing parameter and
run the program again.
MAX lets you set the maximum value of the vertical axis in the plot. The
default value is usually fine whenever you are doing one plot. However, if you
are comparing two or more plots, it is helpful to put the axes on the same
scales. We suggest you run HIST without this option first for each of your
plots; then set MAX based on the maximum value of the vertical axis in all of
your plots.
Gary King
2006-01-07
