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For a data set of n values x1, x2,..., xn it is given that sum(xi²) = 300 and sum(xi) = 50. Which of the following is a possible value of n?

1. 4
2. 6
3. 7
4. 10

Correct answer: 10

Solution

Non-negative variance requires 300/n - (50/n)² >= 0, simplifying to 300n >= 2500, so n >= 8.34. Among the options, only n = 10 satisfies this constraint.

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