User blog comment:Linathan/Unit Spotlight: Rose Empress Tora/@comment-26231443-20150411033314/@comment-26140304-20150411034058

The calculations come from the TI-84 function called binomcdf(. This function calculates the probability of an event occuring successfully out of the number of given trials. Since we only care about the probability of status ailments occuring, we take 1 (which resembles 100%) and subtract the probability of status ailments not occuring at all from 1.

If you're interested to learn more about binomial cumulative distribution, maybe this link can help: Link