Nick Cox wrote:
> -histogram- needs no improvement. It is perfect. (No, I didn't write
> it.)
>
> More seriously, this touches upon some issues flagged on Statalist
> earlier this year.
>
> Part of the issue may be terminological, as in a concurrent thread.
>
> 1. I take a histogram, strict sense, to refer to a display of
> frequencies
> (fractions, densities) of a continuous variable divided into classes
> (bins).
> The hallmark of a histogram as produced by proper statistical software
> is
> that adjacent bars touch. (If this isn't true, you haven't got a
> proper
> histogram, or you haven't got proper statistical software.)
I second Nicks strict definition of histograms. However, I think that Statas
implementation of histograms is slightly to "strict". Histograms refer to a
display of densities of a continuous variable devided into classes. But
there is no reason that all the classes have equal width. One can draw
histograms with bins of different width and heights proportional to the
densities. The area of these bins are proportional to the fraction, than.
To my knowledge this is the original definition of histograms. Stata
histograms are special cases. The more general case seem to be less
vulnerable against the decisions about the number of bins and/or the origin
than the Stata implementation. But this is just my very personal impression.
Anyway, there is no reaseon not to allow bins with different widths.
-histogram- needs improvement. It is not perfect.
(Unfortunatelly, the implementation of histograms with different widths in
hist3.ado is far from beeing perfect ...)
regards
uli
--
[email protected]
*
* For searches and help try:
* http://www.stata.com/support/faqs/res/findit.html
* http://www.stata.com/support/statalist/faq
* http://www.ats.ucla.edu/stat/stata/
