EVs work a lot differently in Gens 1 and 2 (which is what this equation is for). In those games, EVs can go up to 65535 each, and the entirely of the base stats of a defeated Pokémon are gained as EVs (rather than adding 1/2/3 as in later games). Because of the way it works, each stat's EVs need to be square-rooted in order for them to provide a reasonable boost to the Pokémon's stats.
I would ignore that equation if I were you, since it's only for the old games.