I'm reading about the familywise error rate here and trying to put it into perspective. According to this, we calculate FWER = 1 - (1 - alpha)^n. In their example n=10, and with alpha .05, they say this gives 40.1% chance of a type 1 error. Is this practically saying that if i run a study and make 10 comparisons, the probability that an significant result (if one is observed!) is false is 40%? In other words, given that I see any significant, there is a 40% chance that this is false.? So what if I see 4 significant here? It's says approximately ~1.6 of those is false? I think i am right but want to be sure.