Multiple choice

In a colony, the mean age of all the males is $15$ years, and the mean age of all females is $19$ years. Find the condition that must be true about the mean age $m$ of the combined group of male and female in colony.

  1. $m=17$
  2. $m> 17$
  3. $m< 17$
  4. $15< m< 19$
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D Correct answer
Explanation

The combined mean m must lie between the individual means of the two groups. Since male mean is 15 and female mean is 19, 15 < m < 19.

AI explanation

The combined mean of two groups must always lie strictly between the individual means of the groups. Since the mean age of males is 15 and the mean age of females is 19, the mean of the combined group cannot be equal to either extreme. Therefore, the condition that must hold true is 15 < m < 19.

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