/** Approximate Score (Agresti-Coull) Confidence Interval for a Proportion **/
/***********************************************************
Macro ac does 1 sample Agresti-Coull confidence interval for a proportion.
INPUT:
 dataset: input data set
 variable: variable to be analyzed. This should take 2 values, preferably 0 and 1.
           The population proportion of 1's is estimated.
 level: confidence level
OUTPUT:
 sample proportion and confidence interval
***********************************************************/
%macro ac(dataset,variable,level);
%let alpha2=%sysevalf(1-&level);
proc sort data=&dataset;
 by descending &variable;
run;
proc print;run;
 proc freq data=&dataset order=data;
 tables &variable/binomial(ac) alpha=&alpha2;
 ods select binomialCLs;
run;
%mend ac;
/***********************************************************
Sample call: First submit the above macro code, then the code below.
This first part reads in the LDL data from class, and converts each
value to 0 (LDL increase) or 1 (LDL decrease).
***********************************************************/
data ldl;
 input decrease_ldl @@;
 decrease=(decrease_ldl>0);
 cards;
-7.6 13.9 27.1 14.8 6.3 42.0 41.7 18.5 31.2 24.0
;
run;
/***********************************************************
And this is how the macro is called to get a 95% confidence interval.
***********************************************************/
%ac(ldl,decrease,.95);