I want to calculate the Out-Of-Specification (OOS) probability of my dataset (probability of having a result which is greater than the acceptance limit). I have noticed that my results follow a log-normal distribution. I am thinking about log-transforming all my data and the upper-limit, then calculate the OOS risk based on the normal CDF function of these new results (the distribution of my data is Normal after the transformation).
Is this a correct way to do? If not, can you suggest me a better approach please?
P/S: I am working with SAS and R.