Question

01. What will be the new mean, if it is known that for a group of 10 students,
scoring an average of 60 marks, the best paper was wrongly marked 80
instead of 75 ?
(3 marks)​

Answer 1

Explanation:

average 60

10 students

so total 600

now 1 paper was erroneously marked

hence

600 - 80

= 520

it should be 75

hence the total should be 595

hence new mean

595/10

59.5marks

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Answer 2

Explanation:

Answer:- XBar = Sigma X

N

Sigma X = XBar*N

Sigma X= 60*10=600

Correct value= 75

Incorrect value=80

Xbar=sigmaX +correct value-incorrect value

N

Xbar= 600+75-80

10

Xbar = 59.5

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