Question

The mean of 10 observation is 15.3. If two observations 6 and 9 are replaced by 8 and 14 respectively. Find the new mean.

Answer 1

The mean of $10$ observations = $15.3$

The sum of the $10$ observations = $10\times 15.3=153$

If observations 6 and 9 are replaced by 8 and 14 respectively, then the new sum of 10 observations.

$=153-(6+9)+8+14$

$=153-15+22$

$=160$

So the new mean of $10$ observations $=\frac{160}{10}$

$=16$