Question

The average marks of 100 students were found to be 40 later on it was discovered that a score of 53 was misread as 83.Find the correct arithmetic mean

Answer 1

Given mean marks of 100 students = 40 Sum of marks = 100 × 40 = 4000 Given that one observation is misread as 53 instead of 83 Hence error in reading the marks = 83 – 56 = 30 Correct sum of observations = 4000 – 30 = 3970 Correct mean = 3970/100 = 39.7

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