Find an unbiased estimate of the population variance from the sample 4, 8, 12, 16, 20.

Answer and explanation

Correct answer: D. 40

  1. Step 1: Mean , and . Step 2. Unbiased estimate , which is . Answer: 40. Why not the others: 32: That divides by instead of . 160: That is the sum of squared deviations, not divided by anything. 12: That is the sample mean, not the variance.

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