scott wrote:
>> See my other post; Excel has a function to directly compute a binomial 
>> distribution, apparently. (And cumulatively, if you wish.)
> 
> I need the inverse function though, I want to tell it the cumulative 
> probability (eg 10% and 90%) and it tell me how many successful trials 
> that relates to.  There seems to be no BINOMDISTINV function.

Wikipedia claims that for large N, the binomial distribution 
approximates the normal distribution. (If you plot the normal 
distribution with expected value N * P(H) and varience N * P(H) * (1 - 
P(H)).)

This approximation works best for large N and for P(H) near to 50%.

I presume it's relatively easy to work out the inverse function for a 
normal distribution...

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