# as092 - STAT 854/454 Sampling Theory and Practice Due:...

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STAT 854/454 Sampling Theory and Practice Assignment 2 Due: Wednesday, February 4, in class Format: standard A4 size paper, single-sided, with a cover page 1. Let N = 7 , 800 be the number of public schools in Canada. We wish to estimate p = M/N , where M is the number of schools that have Wireless Internet Access (WIA). (a) Find the required sample size n such that the estimate is accurate within 2 percentage points, 19 times out of 20 under SRSWOR, assuming prior information on p is not available. (b) Re-do (a) assuming p = 5% for the purpose of sample size calculation. (c) If we do inverse sampling with m = 10 under selection without replacement, what is the expected number of schools we have to sample? Assume p = 5% for the purpose of planning. (d) Re-do (c) assuming selection with replacement. 2. Consider a stratiﬁed population with H = 3, N 1 = 500, N 2 = 1000, N 3 = 1500, σ 2 1 = 100, σ 2 2 = 200, σ 2 3 = 225, and we do stratiﬁed simple random sampling. (a) Let
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## This note was uploaded on 11/23/2010 for the course STAT 454 taught by Professor Da during the Fall '09 term at Waterloo.

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