*Copyright @ www.statschoice.com;

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Create a sample dataset

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/********************************************************************************

Setting the height value to null to demonstrate _freq_ variable

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  data class02;
    set sashelp.class;
    if age=16 then do;
        height=.;
    end;
  run;

/********************************************************************************

Code to demonstrate the difference between _freq_ and 'n' statistic

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/********************************************************************************

_FREQ_ variable in the output dataset presents the number of records contributed
'n' statistic represents the number of observations with non-missing value in a particular analysis variable
'nmiss' statistic represents the number of observations with missing value in a particular analys variable
In the output dataset, _freq_ indicates the total number of observations in class02 dataset
'n' statistic for height variable indicates a value of 18 as there are only 18(out of total 19) records with non-missing height value
'n' statistic for weight variable indicates a value of 19 as all 19 observations have a non-missing value

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proc means data=class02;
    var height weight;
    output out=statsfreq2
    n=nheight nweight
     nmiss=nmissheight nmissweight
    mean=meanheight meanweight
    median=medianheight medianweight;
  run;