DATA covprob;
p = .5;
q = 1-p;
z=abs(probit(.025));
zz=z*z;
do n = 10 to 500;
w = zz / (2 * n);
rad = sqrt(2*w*p*q + w*w);
rt = (p + w + rad)/(1 +2*w);
lt = (p + w - rad)/(1 +2*w);
nhat_rt = floor(n*rt);
nhat_lt = ceil(n*lt - 1);
ncurl_rt = floor((n+4)*rt - 2);
ncurl_lt = ceil((n+4)*lt - 3);
p1 = probbnml(p, n, nhat_lt);
p2 = probbnml(p, n, nhat_rt);
cv_hat = p2 - p1;
p3 = probbnml(p, n, ncurl_lt);
p4 = probbnml(p, n, ncurl_rt);
cv_curl = p4 - p3;
output;
end;
keep n cv_hat cv_curl;
run;
PROC plot data = covprob;
plot cv_hat*n = '^';
plot cv_curl*n = '~';
run;
quit;
In what context? Is there a specific part you don't understand?
Are you looking for an explanation of a specific line?
Where did you find this code and what are you trying to do with it?
It looks like some sort of power analysis for (binomial) proportions. But why reverse engineer this undocumented code? Understand the problem and write your own. And document it!
If it is power analysis it's likely proc power would likely be a better implementation as well 🙂
Are you ready for the spotlight? We're accepting content ideas for SAS Innovate 2025 to be held May 6-9 in Orlando, FL. The call is open until September 25. Read more here about why you should contribute and what is in it for you!
Learn how use the CAT functions in SAS to join values from multiple variables into a single value.
Find more tutorials on the SAS Users YouTube channel.