The mean of 20 items is 47. Later it is found that the item

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The mean of 20 items is 47. Later it is found that the item 62 is wrongly written as 26. Find the correct mean.

Later it is found that the item 62 is wrongly written as 26 ,
∴ Difference = 62 – 26 = 36

∴ Required average = 47 +	36
	20

Required average = 47 + 1.8 = 48.8
Second method to solve this question with the help of given formula :
Here, n = 20 , m = 47 , a = 62 , b = 26

Correct Average = m +	(a - b)
	n

Correct Average = 47 +	(62 - 26)
	20

Correct Average = 47 +	36
	20

Correct Average = 47 + 1.8 = 48.8