User blog comment:Linathan/Birthday Special: Q&A/Ask Linathan!/@comment-27508440-20150620045608/@comment-26140304-20150620132147

This takes some explaining to do and it's really only understandable if you've gotten a really good understanding of math and statistics. The probability relies on the number of units you have attacking the enemy, using the formula 1-binomcdf(n, p, r).

n represents the number of trials, which, in this case, means the number of units attacking.

p represents the probability, which is the chance of inflicting.

r is the number of successes. We can leave this as 0.

The reason why we use binomcdf to subtract from 1 is because we want to find out the probability of an instance that occurs at least once, given that r = 0.

I'll make a Mechanic Spotlight this Monday talking about this.