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help for ^hist3^
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Draws Histograms for Intervals of different size ------------------------------------------------

^hist3^ varname [^if^ exp] [^in^ range]^ [,^ ^v^alues^(^numlist^)^ graph_op > tions ]

Description -----------

^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 -------

^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 --------

. ^hist3 price^ . ^hist3 price, v(3500(2000)9000,10000,18000)^ . ^hist3 price, v(3500(1000)8000,10000,15000) xlab(3000(2000)16000)^

Authors -------

Ulrich Kohler, Univ. Mannheim ukohler@@sowi.uni-mannheim.de

Steffen Kuehnel, Univ. Giessen

Also see --------

Manual: [g] histogram On-line: help for @graph@, @hist2@ (if installed)