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Unformatted text preview: B be the proportion of insect killed by Spray B. Since n A = n B = 200 with p ^ A = .6 and p ^ B = .45, the sampling distribution of p ^ A- p ^ B is approximately normal. Test Statistic: = .05 RR : z > 1.645 Calculation: Decision: Reject the null hypothesis. Conclusion: There is enough evidence to indicate that Spray A is more effective than Spray B. The p-value = P(z > 3.04) = .5 - .4988 = .0012. If the null hypothesis is true and the two insect sprays are equally effective a difference as large as this one would occur by chance 12 times in every 1000. Hence, there is evidence to indicate that Spray A is more effective than Spray B. 90% confidence interval for p A- p B We are 90% confident that Spray A kills between 7% and 23% more insects than Spray B....
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This note was uploaded on 12/11/2011 for the course STA 3123 taught by Professor Staff during the Fall '08 term at FIU.
- Fall '08