Evs. Ah, here we go. EVs are determined by the Pokemon you fight. I believe Purrloin gives out 1 Attack EV, and every 4 make another stat point.
Ex: You fight 4 Purrloin, then level up. You get another Atk point!
However, You have the power bracer.
That means, if you fight 4 Purrloin, each one gives you 5 Atk EVs, so you would have 20 Atk Evs, so once you level up, you get 5 Atk points!