Question

The avergae height of $20$ students in a class was calculated as $160$cm. On verification it was found that one reading was wrongly recorded as $132$cm instead of $152$cm. Find the correct mean height.

Answer 1

Given the average height of $20$ students in a class was $160$ cm

Then, total height of $20$ students $=160\times 20=3200$

But in average, one reading was wrongly recorded as $132$ cm instead of $152$ cm

Then difference of height wrongly recorded $=152-132=20$ cm

Then total height of $20$ students after correction $=3200+20=3220$ cm

Then correct mean height $=\frac{3220}{20}=161$ cm