There are SO many factors involved in growing that effect your yield.. Literally EVERYTHING from food, to light to Co2 and humidity... Sounds to me like they have not had the most optimum conditions, so you shouldnt be expecting much as far as quality or quantity go.. But if your plant is 2.5ft tall in the first week of bud.. it will proabably reach at least 4-5 ft at maturity.. and even if grown poorly.. should yield at least 2-4 ounces. Being that this is only the first week of flower.. you still have LOTS of oppertunity to get some good food and good lights running on that plant.. the more you do for it.. the more you will get in the end! Just remember.. if you go cheap.. you GROW cheap! I have a friend with 3 out door plants that were roughly the same hieght at the start of flower.. he is expecting to take down at least a pound per plant... its all in how you grow it man!