Multiple choice

The mean of $25$ observations is $32$. It was later discovered that $38$ and $29$ are misread as $25$ and $42$. Find the correct mean.

  1. $36$
  2. $32$
  3. $34$
  4. $33$
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B Correct answer
Explanation

Initial sum = 25 * 32 = 800. Correct sum = 800 - 25 - 42 + 38 + 29 = 800. The sum remains the same, so the mean remains 32.

AI explanation

The initial sum of the 25 observations is 25 multiplied by 32, which equals 800. The correct sum is found by removing the misread values and adding the actual values, calculated as 800 minus 25 minus 42 plus 38 plus 29, which equals 800. Dividing this correct sum by 25 gives the correct mean of 32.

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