I answered a question just now, where I said
Actually, you are calculating the false positive rate (FPR) instead of the false positive, it seems that wiki example uses this term in the non-rigorous way.
I am concerned I misuse the expression, so, "in the non-rigorous way" or "in a non-rigorous way", which one is idiomatic?
If you have a more idiomatic and clear expression about this, please let me know.