Binomial and Poisson distribution

[maureen]

Hello

I want to generate a random sample from Binomial distribution (it will be included inside a loop) and another one from Poisson distribution.

How can I do this?

Thanks for your help

[IanWakeling]

In SAS/IML there are essentially two ways.  The random sample can be generated one at a time with the usual Base SAS functions.

  call streaminit(1234);

  do i = 1 to 10;

    b = rand('binomial', 0.05, 20);  /* p=0.05  n=20 */

    p = rand('poisson', 5);          /* lambda=5 */

    print b p;

  end;

However the RANDGEN call is usually the best option.  In general it is more efficient not to use a loop and generate the random numbers all at the same time.

  b = j(10, 1);

  p = j(10, 1);

  call randseed(4321);

  call randgen(b, 'binomial', 0.05, 20);

  call randgen(p, 'poisson', 5);

  print b p;

[Rick_SAS]

Ian's answer is correct. I will add that if you are only going to simulate ONE sample (that is, not inside a loop), you can use the newer RANDFUN function in SAS/IML 12.3: Convenient functions vs. efficient subroutines: Your choice - The DO Loop

Since you mention the binomial and Poisson distribution together, I wonder whether you are forming a compound distribution? If so, see this article: A different way to interpret the negative binomial distribution - The DO Loop