WHIRLWIND EXPLANATION: Pokémon have a fixed, permanent score from 0 to 31 for each stat that affects how good that stat can ever get.

This calculator will figure out that score (called a "gene" or, more obtusely, an "IV") for you, so you can discard the unworthy. It's more accurate for higher-level Pokémon, so it's helpful to go into a level 100 wifi battle with someone and check your Pokémon's stats from there.

Stat calculator

Arbok
Arbok 		Base
stats		 Stats Effort Stats Effort Possible genes (IVs)
Level Level
HP 60
183–208
27–28
Attack 95
155–179
9
Defense 69
114–138
31
Special Attack 65
107–132
27–28
Special Defense 79
129–154
30
Speed 80
131–155
30–31

Hmm, I need more information to figure out your Pokémon's genes exactly. Try raising it to level 80 and entering its new stats.
Remember: if your Pokémon battles at all, you'll need to track the effort it gains. Consider saving your game and using Rare Candy instead.

And for your copy/pasting pleasure:

27–28 HP; 9/31 Physical; 27–28/30 Special; 30–31 Speed

or start over