1) Yes. You can know for sure if you visit the girl in the marketplace in Slateport City next to the man who sells vitamins. If she gives you an effort ribbon, ya can't EV train. If she doesn't, ya can.Originally Posted by Xx Ninja xX
2) Do the box trick. I think it still works in RuSa. Deposit your pokemon, and withdraw it.
3) Well, EV's and IV's are separate, I think. EV's are the values/points from the battles you fight in-game that improves your stats. IV's are concrete, determined from when you first encounter your pokemon, and determine how high your low your stats are... but I'm probably sure you know all that already. How they're related? They're just the stats system in Pokemon. I don't know. :p
4) I'm trying to figure out myself. There's this formula on serebii.net, but I'm getting lost on that...
You can go to Meowth346's site and go to his IV calculator. But you have to know how many EV's your pokemon has.
And if you didn't know already, you can only get 510 total EV's. 255 max per stat. Everyone usually does 252/252/6, since every 4 EV's is 1 pt.