Generating Sample Means From Uniform Distribution

[UCFtigers2017]

Hello. I need to take a sample of 10 random numbers from the Uniform(0,1) distribution then calculate the sample mean. I then need to do this 100 times so that I get 100 sample means all from samples of size 10.  Then I need 100 sample means from sample size 100. Then continues on for a total 7 different sample sizes. The resulting data set should have two columns: 

1.  The sample size of the sample that the sample mean was calculated from 

2. The sample mean

It should have 700 entries. 100 for each sample size. I started with nested for loops but I am stuck on how to calculate the sample mean once I obtain the sample. See code below

data uniform (drop = x);
 do n = 10, 100, 200, 500, 1000, 5000, 10000 ;
      do i = 1 to 100 ;
          do a = 1 to n ;
             x = rand('Uniform');
          end ;
          y = mean(x);                 /* not right.*/
          output ;
      end;
end;
run ;

I know that this does not work because y = mean(x) will just take the mean of one value- the value of x on the nth loop. I can't figure out how to get the mean of just the sample taken in the third do loop. 

Thanks. 

[PaigeMiller · Accepted solution]

You can do this in a data step, you add up all the 10 random numbers and divide by 10.

I would output the individual x values, and then compute the means in PROC SUMMARY

proc summary nway data=have;
     class n i;
     var x;
     output out=means mean=x_mean;
run;

[UCFtigers2017]

Thanks, I summed and divided in the data step. 

data uniform1 (drop = x);
   do n = 10, 100, 200, 500, 1000, 5000, 10000 ; 
     do i = 1 to 100 ; 
       sumx = 0 ; 
          do a = 1 to n ; 
             x = rand('Uniform');
             sumx + x ;
             meanx = sumx / n ;
           end ;
        y = meanx ;
        output ;
    end;
  end;
run ;