Question

Arithmetic mean of nine observations is calucated as 38 . but in doing so ,an observation 27 is mistaken for72. find the actual mean of the data

Answer 1

given,
no of observations=9
mean of observations =38
sum of observations= no of observations*mean of observations
=38*9
=342
27 is removed and 72 is added from sum
=342-27+72
=387
the new sum of observations=387
no of observations=9
mean of observations=sum of observations/no of observations
=387/9
=43