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help for moments
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Moment-based statistics

        moments [varlist] [if exp] [in range] [weight] [, allobs
                 format(numeric_format(s)) matname(matrix_name)
                 tabdisp_options variablenames ]

        moments varname [if exp] [in range] [weight] [, allobs by(varlist)
                 format(numeric_format(s)) matname(matrix_name)
                 tabdisp_options ]

    by ... : may be used with moments:  see help on by.

    aweights and fweights are allowed; see help weights.


Description

    moments calculates mean, standard deviation, skewness and kurtosis for
    varlist. Any string variables in varlist are ignored.


Options

    allobs specifies use of the maximum possible number of observations for
        each variable. The default is to use only those observations for
        which all variables in varlist are not missing.

    by() specifies one or more variables defining distinct groups for which
        moment-based statistics should be calculated. by() is allowed only
        with a single varname. The choice between by: and by() is one of
        precisely what kind of output display is required. The display with
        by: is clearly structured by groups while that with by() is more
        compact. To show moments for several variables and several groups
        with a single call to moments, the display with by: is essential.

    format() controls the display format of mean, standard deviation,
        skewness and kurtosis, as follows. Up to four numeric formats may be
        given. The first numeric format given controls the display of the
        mean; any second numeric format that of the standard deviation; any
        third numeric format that of the skewness, and any fourth numeric
        format that of the kurtosis. Formats not specified default to %9.3f.

    matname() specifies the name of a matrix in which to save the results of
        (the last set of) calculations. There will be 5 columns.  The columns
        will contain n, mean, standard deviation, skewness and kurtosis.

    tabdisp_options are options of tabdisp other than format().

    variablenames specifies that the variable names of varlist should be used
        in display. The default is to use variable labels to indicate a set
        of variables.


Examples 

    . moments

    . moments price-foreign
 
    . moments price-foreign, format(%5.1f %5.1f)

    . bysort rep78: moments mpg


Author

    Nicholas J. Cox, University of Durham, U.K.
    n.j.cox@durham.ac.uk


Also see 

    help for summarize, help for tabstat