The mean of 100 observations is found to be 40. If at the time of computation two items are wrongly…
The erroneous total is 100*40=4,000. Replacing 30 and 27 by 3 and 72 gives 4,000-30-27+3+72=4,018, so the corrected mean is 40.18, (3).
Choose your answer
The mean of 100 observations is found to be 40. If at the time of computation two items are wrongly taken as 30 and 27 instead of 3 and 72, find the correct mean.
Answer and explanation
Correct answer C
The erroneous total is 100*40=4,000. Replacing 30 and 27 by 3 and 72 gives 4,000-30-27+3+72=4,018, so the corrected mean is 40.18, (3).
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RPSC Assistant Professor (College Education)