The mean body ma index (BMI) for boy of age 12 year i 23. 6. An invetigator want to tet if the BMI i higher in 12 year old boy living in New York City. How many boy are needed to enure that a two ided tet of hypothei ha 80% power to detect a difference in BMI of 2 unit? Aume that the tandard deviation in BMI i 5. 7