SOLUTION: Respected Sir , Please help me to solve this question, I will be very grateful for your help If there are two groups with 75 and 65 as harmonic means and containing 15 and 13 o

Algebra ->  Average -> SOLUTION: Respected Sir , Please help me to solve this question, I will be very grateful for your help If there are two groups with 75 and 65 as harmonic means and containing 15 and 13 o      Log On


   

Question 487753: Respected Sir ,
Please help me to solve this question, I will be very grateful for your help
If there are two groups with 75 and 65 as harmonic means and containing 15 and 13 observations then the combined HM is given by
As the answer given is : 70.36
Please help me to simplify this !!!
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
i think it would be a weighted average that we are looking for.
the group with an average of 75 harmonic means had 15 observations.
the group with an average of 65 harmonic means had 13 observations.
the answer given is 70.36
the quick way is to test my hypothesis and see if it comes up with the right answer.
(75 * 15 + 65 * 13) / (15 + 13) = (1125 + 845) / (28) = (1970) / (28) = 70.35714286 which rounds off to 70.36
my hypothesis was correct.
you are taking a weighted average.
that's your answer.