Talk:Tentacle Spike/@comment-83.238.225.153-20171104152842/@comment-89.228.10.230-20171114203154

"That's a total chance of 0.00038% to get 9 out of 18 possible spikes"

That's wrong.

The chance of getting exactly 9 spikes out of 18 tentacles is around 18.55%.

The chance of getting at least 9 out of 18 is around 59.27%. And then of course getting 8 or less out of 18 is around 40.73%.

The Math (bernoulli process):

9 out of 18: 0.5^9 * 0.5^9 * (18 choose 9)

// chance of getting 9 * chance of not getting the rest (9) * number of these specific outcomes

(18 choose 9) = 48620

at least 9: just the sum of the chances of getting 9 until 18.