Multiple choice

Nitika chose 12 numbers randomly. The sum of 12 numbers is 18 and the sum of their square is 30. What is the variance of the series?

  1. 0.5

  2. 0.25

  3. 0.6

  4. 1.25

  5. None of these
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B Correct answer
Explanation

Variance is calculated as (Sum of squares / n) - (Mean)^2. Here, n = 12, Sum of squares = 30, and Mean = 18/12 = 1.5. Variance = (30/12) - (1.5)^2 = 2.5 - 2.25 = 0.25.

AI explanation

The variance formula is the sum of squares divided by n, minus the square of the mean. The mean is 18 divided by 12, which is 1.5. The variance is 30 divided by 12, minus the square of 1.5, resulting in 2.5 minus 2.25, which equals 0.25.

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