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  • The mean of a set of 150 observations is 100. It was later discovered that five observations, 110, 112, 115, 118, and 120, were incorrectly recorded as 75, 78, 80, 82, and 85. What is the correct m

The mean of a set of 150 observations is 100. It was later discovered that five observations, 110, 112, 115, 118, and 120, were incorrectly recorded as 75, 78, 80, 82, and 85. What is the correct mean?

 

Option: 1

99.2


Option: 2

100.1


Option: 3

102.4


Option: 4

103.7


Answers (1)

best_answer

To find the correct mean, we need to adjust the five incorrectly recorded observations and recalculate the mean.

The sum of the original 150 observations is 100\times 150= 15000.

We need to subtract the incorrect values (75, 78, 80, 82, and 85) and add the correct values (110, 112, 115, 118, and 120) to the sum.

Corrected sum = (15000 - 75 - 78 - 80 - 82 - 85) + 110 + 112 + 115 + 118 + 120 = 15000 - 75 - 78 - 80 - 82 - 85 + 110 + 112 + 115 + 118 + 120 = 15017.

The correct mean is the corrected sum divided by the number of observations (150).

Corrected mean = 15017 / 150 = 100.11333333333333.

 

Posted by

HARSH KANKARIA

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