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Calculate the variance of the data set: 8, 12, 13, 15, 22.

1. 21
2. 21.2
3. 21.4
4. None of these

Correct answer: 21.2

Solution

Mean = 70/5 = 14. Squared deviations from mean: (8-14)²=36, (12-14)²=4, (13-14)²=1, (15-14)²=1, (22-14)²=64. Sum = 36+4+1+1+64 = 106. Variance = 106/5 = 21.2.

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