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For a 95% confidence ratio, you need 4268 packs. With potions it's 2,100ish, and I just like to say 2,400 since that's where the bonus pack discount maxes out on current packs.

95% confidence for what? getting a GFL?

For getting an even spread of Common-Legendary RF-- You have to have a much higher amount of packs for a 95% confidence interval on getting a reliable spread of GF.

How do you define an even spread? Sorry for all the questions, but I'm a stats guy and the threshold where it becomes worth opening packs is a really important metric to me.

The expected percentages of each-- 1.5% Legendary (doubled if using potions), x% Epic, y% Rare, and z% common. Anything less than a 95% confidence interval isn't considered statistically significant-- this is usually used for determining how large a sample size is needed for a research study.

This video is pretty good, and it goes into standard deviations a bit too.

Oh thanks! Can you show me the exact calculation that led you to the 4268 number?

I can't because I had my statistics professor friend do it. I text him random questions all the time-- we've been friends since we were kids.