Multiple choice

The mean of following distribution is: xi 11 14 17 20 fi 3 6 8 7

  1. 16.4

  2. 14.8

  3. 15.6

  4. 17
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A Correct answer
Explanation

Mean = sum(f*x) / sum(f) = (11*3 + 14*6 + 17*8 + 20*7) / (3+6+8+7) = (33 + 84 + 136 + 140) / 24 = 393 / 24 = 16.375, which rounds to 16.4.

AI explanation

Use the direct method for calculating the mean of a frequency distribution: the sum of (fi times xi) divided by the sum of fi. The sum of (fi times xi) is (3 times 11) + (6 times 14) + (8 times 17) + (7 times 20), which equals 33 + 84 + 136 + 140 = 393. The sum of fi is 3 + 6 + 8 + 7 = 24. Dividing 393 by 24 gives a mean of 16.375, which rounds to 16.4.

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