The mean of marks scored by 100 students was found to be 40. Later on

1.	The mean of marks scored by 100 students was found to be 40. Later on it was discovered that a score of 53 was misread as 83. Find the correct mean.
Answer» Mean marks of 100 students = 40 Sum of marks of 100 students = 100 * 40 = 4000 Correct value = 53 Incorrect value = 83 Correct sum = 4000 – 83 + 53 = 3970 Therefore, correct mean \(=\frac{3970}{100}\) = 39.7

The mean of marks scored by 100 students was found to be 40. Later on it was discovered that a score of 53 was misread as 83. Find the correct mean.

Answer»

Mean marks of 100 students = 40

Sum of marks of 100 students = 100 * 40

= 4000

Correct value = 53

Incorrect value = 83

Correct sum = 4000 – 83 + 53

= 3970

Therefore, correct mean \(=\frac{3970}{100}\)

= 39.7