Question

Question 12
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
$\therefore$ Sum of 50 observations $=80.4\times 50=4020$
But later, we observed that 96 was misread as 69 at one place.
Then, the correct mean $=\frac{\left(\text{sum of 50 observations}\right)-69+96}{50}$
$=\frac{4020-69+96}{50}=\frac{4047}{50}=80.94$
Hence, the correct mean is 80.94.