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help for ^_pesum^ - 1.6.1 - 1/20/00
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Utility to get descriptive statistics for variables in a regression model
-------------------------------------------------------------------------

    ^_pesum^ [^if^ exp] [^in^ range] [,^m^edian ^d^ummy ^t^wo]


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

^_pesum^ gets the mean, standard deviation, minimum and maximum for the
    variables in a regression. Optionally, it determines the medians and
    whether the variables are 0|1|. . Matrices are returned with the first
    column containing statistics for the dependent variables, with the
    remaining columns containing information for the independent variables.

Note: ^_pesum^ assumes that ^_peife^ has been applied to the ^if^
    condition.

Options
-------

^median^ Return ^r(Smedian)^ with medians for the variables.

^dummy^ Return ^r(Sdummy)^ with medians for the variables.

^two^ Return summary statistics for the second equation in for ^zip^ and
    ^zinb^ models.

Returned Results
----------------

Matrices: Colums are in the order dependent variable, independent variables.

    ^r(Smean)^          - means
    ^r(Ssd)^            - standard deviations
    ^r(Smin)^ & ^r(Smax)^ - minimums and maximums
    ^r(Sdummy)^         - 1 if dummy variable, else 0; if ^dummy^ option
                        is specified.
    ^r(Smedian)^        - medians if ^median^ option is specified.

Scalars:  ^r(SN)             - sample size

Example with a Program
-----------------------

    if "`opt'"=="mean"|"`opt'"=="min"|"`opt'"=="max" {
        _pesum `if' `in',`all'
        mat pe_base = r(S`opt')
    }
    else if "`opt'"=="median" {
        _pesum `if' `in',median `all'
        mat pe_base = r(Smedian)
    }

Also see
--------
On-line: help for ^_peife^, ^_perhs^

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Authors: J. Scott Long and Jeremy Freese
         www.indiana.edu/~jslsoc/spost.htm
         spostsup@@indiana.edu