Question

the mean of 25 observation is 10.2 later on it was detected that an observation was taken as - 10 instead of 10 find the correct mean

Answer 1

Hi friend
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Your answer
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Mean of 25 observations = 10.2

Sum of the 25 observations = (25 × 10.2) = 255

Wrong observation = (- 10)

Correct observation = 10

Correct sun of 25 numbers =
Wrong sum - Incorrect observation + correct observation

= 255 - (- 10) + 10

= 255 + 10 +10

= 275

Correct mean = 275/25 = 11

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