sample size and best test to use nominal categorical data

No - ofcourse rates are going to be different they vary via a normal distrubution in each population anyway - you are never going to get the exact rates when you sample a short perios - its not rates I am after - I am after wether there is. statistically significant differance in yur chance of being screened for DV in one group or another - rates dont help sorry
could just be normal variation otherwise - doesnt prove anything - i think you have isinterpreted my question the variance in rates of each group will follow a normal distribution by chance - it could be chance that they are different


Less is more. Stay pure. Stay poor.
Why don't you just provide your data, sample of data, or a made up version of your data - so we can see why a rate difference won't work!