Question

It was found that an observation $8$ was incorrect, this is observation is now replaced by $12$. Find the new mean :

• A. $10.4$
• B. $10$
• C. $10.2$
• D. $14$

Answer 1

The correct option is C $10.2$

Mean $=10\Rightarrow \frac{\sum x_i}{20}=10$
$\therefore \sum x_i=200$
So, correct mean $u^{\prime }=\frac{(\sum x_i)-8+12}{20}=\frac{204}{20}$
Thus, $u^{\prime }=10.2$.
Ans-Option $C$.