Q. The mean of 100 observations was calculated as 40. It was found later on that one of the observations was misread as 83 instead of 53. The correct mean is :
✅ Correct Answer: (B)
39.7
Explanation: The mean of 100 observations = 40
It was found later on that one of the observations was misread as 83 instead of 53 ,
Difference = – 83 + 53 = – 30
∴ Decrease in average = – 30 ÷ 100 = – 0.3
∴ Required average = 40 – 0.3 = 39.7
Explanation by: Tina Singh
The mean of 100 observations = 40
It was found later on that one of the observations was misread as 83 instead of 53 ,
Difference = – 83 + 53 = – 30
∴ Decrease in average = – 30 ÷ 100 = – 0.3
∴ Required average = 40 – 0.3 = 39.7
It was found later on that one of the observations was misread as 83 instead of 53 ,
Difference = – 83 + 53 = – 30
∴ Decrease in average = – 30 ÷ 100 = – 0.3
∴ Required average = 40 – 0.3 = 39.7