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In: Statistics and Probability

Let X1 and X2 be two observations on an iid random variable drawn from a population...

Let X1 and X2 be two observations on an iid random variable drawn from a population with mean μ and variance σ2 (for example, the random variable could be income; X1 could be person 1’s income and X2, person 2’s income). Which of the following is an unbiased estimator of mean income?

All of these are unbiased estimators of mean income.

23X1+13X2

15X1+45X2

Which of the following is the “best” (that is, least-variance) estimator of mean income?

15X1+45X2

23X1+13X2

All of these are "best" estimators of mean income.

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