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Question
Mean of 50 observations was found to be 80.4. But later on, it was discovered that 96 was misread as 69 at one place. Find the correct mean.
Solution
Given, the mean of 50 observations = 80.4
The formula of the mean `(barx)` is:
`barx = (sum_(i = 1)^n x_i)/n`
So, sum of 50 observations = 80.4 × 50 = 4020
Now, according to the question, 96 was misread as 69 at one place.
Therefore, the correct mean will be
= `(("Sum of 50 observations") - 69 + 96)/50`
= `(4020 - 69 + 96)/50`
= `4047/50`
= 80.94
Hence, the correct mean is 80.94.
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Is it the correct answer and why?
