Multiple choice

The mean of $10$ observation is $25$. If one observation namely $25$, is deleted, the new mean is

  1.  $25$
  2.  $20$
  3.  $28$
  4.  $22$
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A Correct answer
Explanation

Sum of 10 observations = 10 * 25 = 250. If 25 is removed, new sum = 250 - 25 = 225. New count = 9. New mean = 225 / 9 = 25.

AI explanation

The sum of the 10 observations is 10 times 25, which equals 250. If the observation 25 is deleted, the new sum becomes 250 minus 25, which is 225. The new number of observations is 9, so dividing 225 by 9 gives a mean of 25.

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