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 : - 37360

T

Tina Singh • 10.85K Points
Tutor II Math

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 :

(A) 39
(B) 39.7
(C) 40.3
(D) 42.7

Correct Answer - Option(B)

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

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