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From a sample of 5 items having values 2, 4, 6, 7, 6, the unbiased estimates of the population mean and the standard deviation are:

Solution

✅ Correct Option: 4

Mean xˉ=2+4+6+7+65=5\bar{x} = \frac{2+4+6+7+6}{5} = 5.

Deviations from mean: −3,−1,1,2,1-3, -1, 1, 2, 1. Squared: 9,1,1,4,19, 1, 1, 4, 1, sum =16= 16.

Unbiased variance s2=16n−1=164=4s^2 = \frac{16}{n-1} = \frac{16}{4} = 4. So s=2s = 2.

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