z-binomial.... that's the one with all the factorials in the formula. Seen that one. And it's understandable that you go to a website since computing factorials gets to very big numbers very quick. Programming those takes special algorithms.

As for the rest, I get it all except in the last sentence, regarding the formula you stated "(score-expected)/standard deviation",

the standard deviation the square-root of the sum of all the variances?
the score is the sum of the individual scores?
the expected is the sum of the individual expected?

Brian