Answer:
7.25
Explanation:
Given :
___________ Sample size __ sample mean
Treatment 1 ____ 5 _______ 4
Treatment 2 ____ 10 ______ 8
Treatment 3 ____ 5 _______ 9
Sample size = (5 + 10 + 5). = 20
Overall mean = ((5*4). + (10*8) + (5*9)) / 20
Overall mean = (20 + 80 + 45) / 20
= 145 / 20
= 7.25