Question

The sum of the deviations of a set of n scores \[x_{_{1}},x_{_{2}}..............,x_{_{n}}\] measured from 50 is -10 and when measured from 46 is 70.Then the mean is

Answer 1

Let \( S= \sum_{i=1}^n x_i
\) then
\[
S-50 n =-10\\
S- 46 n = 70
\]
This will give you S and n and the rest is easy.

Answer 2

You get n=20 and S =990
So the mean is
\[
\frac {990}{20}=\frac {99}2=49.5
\]