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.
Answers
Answered by
6
Question:
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:
The correct mean is 39.7 marks.
Given:
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.
To find:
The correct mean marks of the 100 students.
Explanation:
The mean of marks scored by 100 students was found to be 40.
∴ The sum of the marks of 100 students together found to be as_
(40×100) marks
= 4000 marks.
∴ The sum of the marks of the 99 students instead the miscounted one_
(4000-83)
= 3917 marks.
∴ The actual sum of the marks of the 100 students_
(3917+53) marks
= 3970 marks.
∴ The actual mean mark of the 100 students is_
(3970÷100)
= 39.7 marks.
∴ The correct mean is 39.7 marks.
Similar questions