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help for ^xfrac^
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Tabulation using categories defined by fractions of a cut-off value
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^xfrac^ varname [fweights aweights] [^if^ exp ^in^ range]
			, ^cut^off^(^#^)^ [ ^gp(^gpname^)^ ]

Description
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^xfrac^ provides a specialized tabulation (a 'wrapper' for -tabulate-).
Each valid observation is first partitioned by varname into one of a set
of 20 mutually-exclusive categories, the boundaries of which are defined 
by 'hard-wired' fractions of a user-specified cut-off value (in the same
units as varname), with fractions ranging from 0.1 through to 3.0. This 
classification is then tabulated and, optionally, can be retained 
as a new variable.

In effect ^xfrac^ provides a discrete representation of the distribution 
function for varname.

Example: let varname be a measure of income and the cut-off be mean
income. ^xfrac^ shows the proportion of observations with income
less than 10% of mean income, between 10% and 20% of mean income, 
between 20% and 30% of mean income, and so on (20 categories). 
Cumulative proportions are also shown.

Mandatory
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^cut^off^(^#^)^  The user must specify a value for the cut-off value
                 (in the same units as varname).

Options
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^gp(^gpname^)^ creates a new categorical variable, gpname, containing
	      categories summarising group membership.

Example
-------
. ^sum x [aw=wgt]^
. ^local mean = _result(3)^
. ^xfrac x [aw=wgt], cut(`mean') gp(gpname)^  

Author
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Stephen P. Jenkins <stephenj@@essex.ac.uk>
Institute for Social and Economic Research
University of Essex, Colchester CO4 3SQ, U.K.

Also see
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@pctile@, @xtile@, ^tabulate^, ^cumul^. 
Manual: [R] ^pctile^, [R] ^tabulate^, [R] ^cumul^.
^sumdist^ (if installed)
