Random velocity for particle effect

I was looking for the best way to randomize the velocity of a particle effect (as in for each particle emitted), limited between set limits? Are there any good examples of how this can be done?
I also need the particle effect to be in a hemisphere, but that can be set in the actual options of the particle effect so it should be fine.

In the main settings, there is a small dropdown next to the Start Speed option.
Change it to Random Between 2 Constants.