Re^2: Fastest way to calculate hypergeometric distribution probabilities (i.e. BIG factorials)?

[Anonymous Monk]

I could be mistaken but I think this calculates the probability of i successful selections, not i or more successful selections as claimed above. For the cdf, prob of i or more successes, you need to do the following:

my $hypercdf = 0;
for (my $iref=$i; $iref < min($N,$n); $iref++)
{
  $hypercdf += hypergeom($n,$m,$N,$iref);
}
print $hypercdf;

[Alokito]

You may need a less than or equal to in the condition of the for loop. This probably won't make a difference in most cases, as the final probability is usually very small.

my $hypercdf = 0;
for (my $iref=$i; $iref <= min($N,$n); $iref++)
{
  $hypercdf += hypergeom($n,$m,$N,$iref);
}
print $hypercdf;