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

Abomasnow
Abomasnow 		Base
stats		 Stats Effort Stats Effort Possible genes (IVs)
Level Level
HP 90
158–174
15–16
Attack 92
102–118
1–2
Defense 75
84–100
13–14
Special Attack 92
102–118
13–14
Special Defense 85
95–111
2–3
Speed 60
68–85
24–25

Hmm, I need more information to figure out your Pokémon's genes exactly. Try raising it to level 54 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:

15–16 HP; 1–2/13–14 Physical; 13–14/2–3 Special; 24–25 Speed

or start over