xkcd explains it better than I can. Basically if you pick p values that give 95% certainty 20 times you're probably going to "discover" at least one falsehood.

xkcd explains it better than I can. Basically if you pick p values that give 95% certainty 20 times you're probably going to "discover" at least one falsehood. https://xkcd.com/882/ https://xkcd.com/882/