Q20 of 79 Page 25

The mean of 200 items was 50. Later on, it was discovered that the two items were misread as 92 and 8 instead of 192 and 88. Find the correct mean.

The mean of 200 items = 50

Then the sum of 200 items = 200 * 50


= 10,000


Correct values = 192 and 88


Incorrect values = 92 and 8


Therefore, correct sum = 10,000 – 92 – 8 + 192 + 88


= 10,180


Therefore, correct mean =


= 50.9


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