??????? 2. (20 pts) Let ( X_{1}, ldots, X_{n} ) be a random sample drawn from a finite population ( left{w_{1}, ldots, w_{N} ight} ).

??????? 2. (20 pts) Let \( X_{1}, \ldots, X_{n} \) be a random sample drawn from a finite population \( \left\{w_{1}, \ldots, w_{N}\right\} \). Find an unbiased estimator of the population variance \( \sigma^ 2 answers