Question 3 [4 mark] Now suppose you instead select these 5 workdays with stratied sampling. In particular 0 In the previous 10 workdays, there are 2 Mon, 2 Tue, 2 Wed, 2 Thu, and 2 Fri. 0 In your stratied sampling, you randomly select 1 Mon, 1 Tue, 1 Wed, 1 Thu, and 1 Fri. Let N, and 3],; be the population size and sample average in each stratum. Let 37m below be the strata- weighted sample mean, which can estimate the population mean. 5 _ Ni _ 21m = :1 Rye Suppose you found the numbers of emails you received in the previous 10 workdays are indeed Mon: 10, 9; Tue: 8, 7; Wed: 6, 5; Thu: 4, 3; Fri 2, 1 What's the variance of 37m given this population? Compared your answer to Question 2h); which of simple random sampling and stratied sampling has smaller variance for their estimator for the population mean, given this population