any theory ) 3. Estimator in statistics, we often use a statistic X to estimate a parameter 6. On one hand, if E(X) we say X is an unbiased estimator of 0. On the other hand, X is called a consistent estimator of 8 if X converges to 9 as sample size increases (i.e., it requires Var(X) decrease as sample size increases). 3.1 If we draw a random sample of size n from a normal population with mean u and variance , please prove that sample variance S is an unbiased estimator of population variance 62. [8%] 3.2 Following 3.1, please prove that sample variance S is a consistent estimator of population variance 2. [8%] H-7 6 -7 P