Hello, I am trying to find the estimated relative risk given certain parameters in a power calculation. The example is for a randomized control trial with 5000 in the treatment group and 5000 in the placebo group with an estimated 2% of the placebo with the outcome.  To solve for the relative risk given these characteristics, I have tried the following code but there is an error message for the RR being missing...even though that is what I am trying to solve for. Any thoughts?   proc power;       twosamplefreq test=pchi relativerisk= . refproportion= 0.02 npergroup = 5000        power = 0.8;  run; ... View more