if you get 2 ounces per plant you did well...

a new grower is lucky to get 1 ounce per plant.

this is a very rough guess.. any number of things can change these numbers
the biggest factor is your light... 400watts.

assuming your plants are healthy and kept smaller than 20 inches before flowering..
And you keep the light veryvery close to the tops of our plants.. with GOOD airflow, you could get 1-3 ounces per plant...

and now you know