Multiple choice

The mean of 22 observations is 10. Two more observations are included and the new mean becomes 11. The mean of two new observations is

  1. 19

  2. 20

  3. 21

  4. 22

  5. Na

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D Correct answer
Explanation

Sum of 22 observations = 22 * 10 = 220. Sum of 24 observations = 24 * 11 = 264. Sum of 2 new observations = 264 - 220 = 44. Mean of 2 new observations = 44 / 2 = 22.

AI explanation

The sum of the initial 22 observations is the mean multiplied by the count, so 10 times 22 equals 220. The sum of the new 24 observations is 11 times 24, which equals 264. The sum of the two new observations is the difference between these totals, 264 minus 220, giving 42. Dividing this sum by 2 gives the mean of the two new observations as 22.