The mean of 72 items was found to be 63. If two of the items were misrecorded as 27 and 9 instead of 72…
The correct choice is: “64.75” Recorded total = 72 × 63 = 4536. Correction = (72 + 90) − (27 + 9) = 162 − 36 = 126, so the correct total = 4536 + 126 = 4662. Correct mean =…
Choose your answer
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 and explanation
Correct answer A
The correct choice is: “64.75”
Recorded total = 72 × 63 = 4536.
Correction = (72 + 90) − (27 + 9) = 162 − 36 = 126, so the correct total = 4536 + 126 = 4662.
Correct mean = 4662 ÷ 72 = 64.75.
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