Multiple choice

The mean of $27$ observations of a variable is $18$. Three more observations are made and the values of these observations are $16,18$ and $50$. What is the mean of these $30$ observations?

  1. $18$
  2. $19$
  3. $25.5$

  4. Cannot be determined due to insufficient data
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B Correct answer
Explanation

Total sum of 27 observations = 27 * 18 = 486. New sum = 486 + 16 + 18 + 50 = 570. New mean = 570 / 30 = 19.

AI explanation

The total sum of the original 27 observations is 27 times 18, which equals 486. The sum of the three new observations is 16 plus 18 plus 50, which is 84. The new total sum for all 30 observations is 486 plus 84, which equals 570. The new mean is 570 divided by 30, which results in 19.

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