Question

mean marks of 100 students was 40.. It was discovered that 53 was misread as 83. Find the actual mean.​

Answer 1

Problem:-

mean marks of 100 students was 40.. It was discovered that 53 was misread as 83. Find the actual mean.

Solution:-

Total mean score = 40

`mean \: = (sum \: of \: observation)/(number \: of \: observations)`

sum of observations

= mean × no of observations

= 40×100

= 4000

After the replacement, sum of new observation will be

=4000-83+53

= 3970

mean of new the observation will be

`= (3970)/(100)`

`= 39.7`

[Hence, the actual mean is 39.7]