Question

Mean of 50 observations was found to be 80.4. But later on, it was discovered that 96 was misread as 69 at one place. Find the correct mean.

Answer 1

Given, the mean of 50 observations = 80.4

The formula of the mean `(barx)` is:

`barx = (sum_(i = 1)^n x_i)/n`

So, sum of 50 observations = 80.4 × 50 = 4020

Now, according to the question, 96 was misread as 69 at one place.

Therefore, the correct mean will be

= `(("Sum of 50 observations") - 69 + 96)/50`

= `(4020 - 69 + 96)/50`

= `4047/50`

= 80.94

Hence, the correct mean is 80.94.