OPTIONS PS=50 LS=75; RUN;
PROC FORMAT;
VALUE onefirst 0="z_0" 1="a_1";
DATA CI_RR_OR;
INPUT vitC cold  n_people;
LINES;
       1   1    302
       1   0    105
       0   1    335
       0   0     76
;
PROC FREQ data=CI_RR_OR ORDER=FORMATTED;
  TABLES vitC*cold / CMH; WEIGHT n_people;
  FORMAT vitC cold onefirst. ;
RUN;

* via binomial regresion;

TITLE risk DIFFERENCE ;

PROC GENMOD DATA=CI_RR_OR;
  MODEL cold = vitc / dist=binomial link=identity;
  FREQ n_people;
RUN;

TITLE risk RATIO ;
PROC GENMOD DATA=CI_RR_OR;
  MODEL cold = vitc / dist=binomial link=log;
  FREQ n_people;
RUN;

TITLE ODDS RATIO ;

PROC GENMOD DATA=CI_RR_OR;
  MODEL cold = vitc / dist=binomial link=logit;
  FREQ n_people;
RUN;