Question

The mean of 72 items was found to be 63. if two of the items were misrecorded as 27 and 9 instead of 72 and 90 respectively, find the correct mean

Answer 1

Mean of 72 = 63
Sum total = 72*63 = 4536

two values were mis-recorded as 27 & 9 instead of 72 & 90
Hence corrected sum = 4536 - (27+9) + (72+90) = 4662
Corrected mean = 4662/72 = 64.75

Answer 2

Answer:

Step-by-step explanation:The mean of 72 items is 63

⇒  The sum of 72 items =72×63

                                         =4536

It is given that, two values were misrecorded as 27 & 9 instead of 72 & 90.

∴  Corrected sum of 72 items =4536−(27+9)+(72+90)

                                                 =4662

⇒  Correct mean of 72 items =4662/72=64.75