STAT 3502 - STAT 3502 Assignment # 4 Total mark=25 Fengbo...

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STAT 3502 Assignment # 4 Total mark=25 Fengbo Cui 100719108 Aug 9, 2010

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2. In a survey of 4720 American, 708 of them were overweight. calculate and interpret a 99% confidence interval for the proportion of all American who are overweight.[3] n= 4720 X=708 p=X/n=708/4720=0.15 q=1-p=1-0.15=0.85 p 3. For a sample of 69 healthy trees, the sample mean of dye-layer density was 1.028 and the sample standard deviation was 0.163. a. Calculate a 95% CI for the true average dye-layer density for all such trees.[2] b. Suppose the investigators had made a rough guess of 0.16 for the value of a before collecting data. What sample size would be necessary to obtain an interval width of 0.05 for a confidence level of 95%?[2] a. n= 69 X=1.028 s=0.163 95% CI is b. The appropriate sample size is 39. 5. Researchers have found that deep-brain stimulator implants have helped patients control many of the symptoms of Parkinson's disease. Suppose that 50 patients with the disease are randomly selected and 8 are identified to be suitable candidates for the implant. Find a 99 percent confidence interval for the
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This note was uploaded on 09/27/2010 for the course STAT 104157 taught by Professor Jhonbran during the Summer '09 term at California Coast University.

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STAT 3502 - STAT 3502 Assignment # 4 Total mark=25 Fengbo...

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