How does changing a Pokemon's level from LV100 to LV50 work?

Question

How are the stats (HP, Atk, SAtk, Def, SDef, Spd) determined?
Like on Battle Subway, Flat Battle....

Comments

well it will be around half plus around a extra 5-7 because of stats from when hatched i guess

Answer 1

Flat Battle is a battle mode introduced and exclusive only to Pokémon HeartGold and SoulSilver found at the Pokémon Communication Club Colosseum. Like the Battle Tower and related Battle Frontier facilities, any Pokémon above level 50 will have its stats and level reduced to its level 50 version, while keeping all its moves and accumulated EVs.

-Bulbapedia

So basically, It reduces the base stats to when it was level 50, taking in account all of the evs you have acquired even if it wasn't there when you were level 50.

Answer 2

It's just the stats the Pokemon had when it was at level 50. If it was caught at a higher level, it's supposed stats without EVs.