The mean of 9 observations is 43. Later, it was found that 59 was misread as 69. What would be the correct mean? (correct to two decimal places).
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 41.89
A misread value is corrected in the sum, not in the mean: the wrong value is taken out of the sum and the right one put in, and the new sum is divided by the number of observations again.
Wrong sum \(=9\times43=387\)
Correct sum \(=387-69+59=377\)
Correct mean \(=377\div9=41.89\) (to two decimal places)