Well, yes...and no. Electro Ball deals more damage on a paralyzed Pokemon, but depends on the Pokemon's ability. Specifically, Quick Feet.
The Speed values used take all modifiers into account (including stat stages, paralysis, held items such as the Iron Ball, and Abilities such as Slush Rush).
While a Pokémon with this Ability has a status condition, its Speed is increased by 50%. Additionally, a Pokémon with this Ability does not lose Speed due to paralysis.
Because paralysis lowers speed of an opponent, Electro Ball will take paralysis into account, making the move stronger. However, if you paralyze a Pokemon that has the ability Quick Feet, Electro Ball can become weaker since a Pokemon with the ability Quick Feet ignores the speed drop from paralysis. Hope this helps.