Question

1. The average teenager gets 7 hours of physical activity in a given week, with a standard deviation of 0.5. Michelle Obama’s Lets Move! Initiative encourages schools to add more physical activity into the school day. They add additional physical education classes and extra recess activities. 25 students are selected at random and report how many hours of physical activity they had in the last week. The mean is 7.18.

1. Find Cohen’s d.

2. What is the strength of this value? Does this mean that there is a lot of overlap or a small amount of overlap?

Answer 1

given data,
The average teenager gets 7 hours of physical activity in a given week
with a standard deviation of 0.5. Michelle Obama’s Lets Move.
25 students are selected at random
The mean is 7.18
using formula
cohen's d effective size = modulus of ( sample mean - population mean )/ standard deviation
cohen's d effective size = modulus of (7-7.18)/(0.5)
cohen's d effective size = 0.18/0.5
a.
cohen's d effective size = 0.36
if cohen's d value is 0.20 small
cohen's d value is 0.50 medium
cohen's d value is 0.80 large value
b.
so that cohen's d value is 0.36
it is mean that there is a small amount of overlap
strength value is between 0.20 to 0.50