SAS Change the Proportion of a Random Sample

问题:

Is there a way to change and manipulate the proportion of a variable in SAS in random sampling?

Lets say that I have table consisting 1000 people. (500 male and 500 female)

If I want to have a random sample of 100 with gender strata - I will have 50 males and 50 females in my output.

I want to learn if there is a way to have the desired proportion of gender values?

Can ı have a random sample of 100 with 70 males and 30 females ?

回答1:

PROC SURVEYSELECT is the way to do this, using a dataset for n or samprate instead of a number.

data strata_to_Sample;
  length sex $1;
  input sex $ _NSIZE_;
datalines;
M 70
F 30
;;;;
run;
proc sort data=strata_To_sample;
  by sex;
run;

data to_sample;
  set sashelp.class;
  do _i = 1 to 1e5;
    output;
  end;
run;
proc sort data=to_Sample;
  by sex;
run;

proc surveyselect data=to_sample n=strata_to_sample out=sample;
  strata sex;
run;

回答2:

Generally that is what proc surveyselect is for.

But for a quick and dirty datastep solution:

data in_data;
    do i= 1 to 500;
        sex = 'M'; output;
        sex = 'F'; output;
    end;
run;
data in_data;
    set in_data;
    rannum = ranuni(12345);
run;
proc sort data= in_data; by rannum; run;
data sample_data;
    set in_data;
    retain count_m count_f 0;
    if      sex = 'M' and count_m lt 70 then do; count_m + 1; output; end;
    else if sex = 'F' and count_f lt 30 then do; count_f + 1; output; end;
run;    
proc freq data= sample_data;
    table sex;
run;