Question

The algebric sum of deviations of $10$ observations measured from $15$ is $7$. The mean is

• A. $105$
• B. $70$
• C. $15.7$
• D. none of these

Answer 1

The correct option is C $15.7$

We know that

$Mean=\frac{sumofobservation}{numberofobservation}$

Since, the sum of observation is $=7$

Number of observation $=10$

Therefore,

Mean$=\frac{7}{10}=0.7$

But, here observation starts from $=15$

Therefore,

Mean$=15+0.7=15.7$

Hence, the mean is $15.7$.