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Unformatted text preview: Please derive the general formula first. Solution: First we derive the general formula. ( ) 1 ( ) 1 ( ) 1 / / / P X E P E X E E X E P n n n - = --- = --- = -By the central limit theorem, when the sample size is large, 2 / 2 / 2 (0,1) / / z X E Z N z n E n n- = : & When is unknown, we can estimate its value using the sample standard deviation, here being s = 150 Now we plug in the values to obtain the answer for the given problem: 2 2 / 2 1.96*150 216.09 217 20 z n E . Therefore a total of 217 days must be sampled....
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This note was uploaded on 11/14/2010 for the course AMS 312 taught by Professor Zhu,w during the Spring '08 term at SUNY Stony Brook.
- Spring '08