Question

Where am I wrong?

I have 5 subjects with 100 maximum marks to score. I got 95 in subjects A,B,C,D and 92 in subject E. The average is 94.4.
But when i take average as (average of subjects with 95)+(average of subjects with 92) i get 93.5. Why average of average is not the true average?

Answer 1

You need to add all of the raw scores together before taking the average.

Explanation:

What you are describing appears to me like this:

`((sum(A, B, C, D))/4+E)/2`

If you do it that way, you get an average of 93.5. However, that is not a valid way to average 5 items. That is the average of two averages. Instead, take the average of all 5 subjects:

`mu=(sum(A,B,C,D,E))/5`

`mu=(95+95+95+95+92)/5=(4xx95+92)/5`

`mu=472/5`

`mu=94.4`