>>38471396not that anon, but that depends on what base stat is higher, HP or defense/special defense. Normally, you want to invest on the lower of the two:
example: ordinary alomomola vs shadow ball
>165 base HP>45 base sp.defHP investment:
>0 SpA Gengar Shadow Ball vs. 252 HP / 0 SpD Alomomola: 202-238 (37.8 - 44.5%) -- guaranteed 3HKOSp. Def investment:
0 SpA Gengar Shadow Ball vs. 0 HP / 252 SpD Alomomola: 135-160 (28.6 - 33.9%) -- 0.9% chance to 3HKO
Now let's switch alomomola's base HP with its base Sp. Def:
>45 base HP>165 base sp.defHP investment:
0 SpA Gengar Shadow Ball vs. 252 HP / 0 SpD Alomomola: 70-84 (23.8 - 28.5%) -- 95.5% chance to 4HKO
Sp.Def investment:
0 SpA Gengar Shadow Ball vs. 0 HP / 252 SpD Alomomola: 60-72 (25.9 - 31.1%) -- guaranteed 4HKO
so there, if you are only investing in either one defense or HP, go for the one that's lower.