Board Thread:Question and Answer/@comment-24125853-20160418134247/@comment-2098192-20160421043900

for the 1.25% to .46% unless you have a sample size in excess of 1,000 I wouldn't put too much stock.

If we assume the rate is 1.25% and you have a sample size of 500 (which is probably close) for you to conclude you have a .46% rate instead means you should have 2.3 drops, and you have a roughly 5% chance of having 2 drops or fewer if the rate truly is 1.25%, which means you are boarding on statstical significance, but not quite there yet.

and even when you do get there, remember statistical signifiance is 95%, so 1/20 of those findings is likely wrong, as https://xkcd.com/882/ explains.

And we don't even know if the rate is really 1.25% or if you just got lucky last event.

For such low drop rates you need such a large sample size to conclude anything, it is hard to draw conclusions from a single event unless you are grinding hard.