Question

The mean of 25 observation is 40. Later on it was found that 13 and 21 were misread as 31 and 12. Find the correct mean.​

Answer 1

Answer:

Correct option is

D

39.7

⇒ Given mean 100 observation =40

⇒ Sum of observations =100×40=4000

⇒ Given that one observation is misread as 83 instead of 53

⇒ Hence error in reading the observations =53−83=−30

⇒ Correct sum of observations =4000–30=3970

⇒ Correct mean =

100

3970

=39.7