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help for ^hist3^
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Draws Histograms for Intervals of different size
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^hist3^ varname [^if^ exp] [^in^ range]^ [,^ ^v^alues^(^numlist^)^ graph_options ]
Description
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^hist3^ draws histograms for intervals of different size. To do this,
varname is grouped into intervals according to the cutpoints in the
value-option. Then for each interval a bar is drawn with width equal to
the width of the intervall and height equal to f_j/(h_j*n), where
f_j = the absolute frequency of the interval j, h_j = the width of j and
n = number of nonmissing observations. The heigths of the bars therefore
reflect the density of the interval, and the area reflect the frequency
of the interval.
Options
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^values^(^numlist^) sets the cutpoints to group varname. Usually you will
specify cutpoints within the range of varname. In this case the lower
bound of the first interval is set to the minimum of varname and the
upper bound of the last interval is set to the maximum of varname.
If you choose values outside the range of varname the lower bound of
the first interval is set to the minimum anyway, but the upper bound
of the last interval is set according to the maximum you specified.
If you do not specify values, a histogram with (almost) equal-sized
intervals is drawn. The number of bars is set according to
min(sqrt(n), 10*log10(n)) in this case (See [G] histogram).
graph_options are any of the options allowed with ^graph, twoway^, except pen.
In addition the shortcut xlab without numbers do not work;
see help @grtwoway@.
Examples
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. ^hist3 price^
. ^hist3 price, v(3500(2000)9000,10000,18000)^
. ^hist3 price, v(3500(1000)8000,10000,15000) xlab(3000(2000)16000)^
Authors
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Ulrich Kohler, Univ. Mannheim
ukohler@@sowi.uni-mannheim.de
Steffen Kuehnel, Univ. Giessen
Also see
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Manual: [g] histogram
On-line: help for @graph@, @hist2@ (if installed)