Question

The mean height of $15$ students is $154cm$. It is discovered later on that while calculating the mean the reading $175cm$ was wrongly read as $145cm$. The correct mean height is

• A. $145cm$
• B. $170cm$
• C. $156cm$
• D. None of these

Answer 1

Answer: (C)

$156cm$

Total height of $15$ students $=\sum x=154\times 15=2310cm$
It was found that $175cm$ was wrongly read as $145$
Correct sum $=2310-145+175=2340cm$
Correct mean $=\frac{2340}{15}=156cm$