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The variance of first 50 even natural numbers is

1. 437
2. 437/4
3. 833/4
4. 833

Correct answer: 833

Solution

The first 50 even natural numbers are 2*(1..50). Variance scales by 2^2=4 relative to the first 50 naturals, whose variance is (n^2-1)/12 = 2499/12. So variance = 4*2499/12 = 833.

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