Asked Apr 14, 2019
  1. The mean body mass index (BMI) for boys age 12 is 23.6. An investigator wants to test if the BMI is higher in 12-year-old boys living in New York City.  How many boys are needed to ensure that a two-sided test of hypothesis has 80% power to detect a difference in BMI of 2 units?  Assume that the standard deviation in BMI is 5.7.


  Alpha = ________

    Z1-α/2= ________

     Z1-β = ________

       ES = ________

          n= ________



Expert Answer

Step 1

The provided information are:


Step 2

The required z-values can be calculated as follows:

Step 3

The value of effect size (ES)...


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