Question

The mean of $12$ observations is $14$. By an error one observation is registered as $24$ instead of $-24$. Find the actual mean.

• A. $10$
• B. $20$
• C. $30$
• D. $40$

Answer 1

The correct option is A $10$

Mean of 12 numbers = $14$
Sum of these 12 numbers = $168$
After replacing the wrong number $24$ with correct number $-24$, sum = $168-24-24$ = $120$
Mean = $\frac{Sum}{Numberofobservations}$ = $\frac{120}{12}=10$