Question

mean of 9 observation is equal to 35 later on it was discovered that an observation 81 was misread as 18 find the correct mean

Answer 1

mean of nine observation=35 (given)

sum of nine observation=35*9=315

,since 81 was misread as 18

sum of new observation =[315-(wrong observation) +(correct observation)]

=315-18+68
=315+63
=378
correct mean=378/9=42

hence the correct mean is 42