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confidence interval homework 3




Question;1.A political pollster is hired to estimate the proportion of voters in favor of Senator Claghorn. He takes a sample of 400 and finds 56%of the voters favor the Senator. A 95% confidence interval for the true population favoring Senator Claghorn is?2. A poll of 100 students revealed that 50 were in favor of returning to the semester system. If p is the proportion of all students in favor of semesters, than 99% confidence interval for p is given by?3. Some scientists believe that a new drug would benefit about half of all people with a certain blood disorder. To estimate the proportion of patients who would benefit from taking the drug, the scientists will administer it to a random sample of patients who have the blood disorder. What sample size is needed so that the 95% confidence interval will have a width of.06?4. A random sample of 900 individuals has been selected from a large population. It was found that 180 are regular users of vitamins. Thus, the proportion of the regular users of vitamins in the population is estimated to be 0.20. An estimate of the standard error of this estimate is?5. A Gallop poll of a sample of 1089 Canadians (total population of 26,000,000) found that about 80% favored capital punishment. A Gallop poll of a sample of 1089 Americans (total population of 260,000,000)also found that 80% favored capital punishment. Which of the following statements is true?A. The Cancadian poll is much more accurate since the larger proportion was surveyed.B. You cannot compare the precision of the two polls since we do not know the confidence coefficient used.C. The American poll is more accurate since they have a larger total population.D Both polls are almost equally precise since they have the same sample size and two populations are relatively large.E. Both polls are equally precise since in both polls 871 of respondents favored capital punishment.6. In a test of Ho: p=0.4 against Ha:p doesn't equal (= sign with slash) 0.4, a sample of size 100 produces produces z=1.28 for the value of the test statistic. Thus the p-value (or observed level of significance) of the test is approximately equal to?7. It is believed that at least 60% of voters from a certain region in Canada favor the free trade agreement (FTA). A recent poll indicated that out of 400 randomly selected individuals, 250 favored the FTA. If we wished to perform a test to determine whether the proportion of those favoring the FTA is greater than 60%, at the 5% level of significance, we would?8. A large supermarket chain will increase its stock of bakery products if more than 20% of its customers are purchasers of bakery products. A random sample of 100 customers found 28% purchased bakery items. A 5% significance test is conducted to determine if the chain should increase it bakery stock. The p-value for the situation is?9.A seed company claims that 80% of the seeds of a certain tomato will germinate if sown under normal conditions. A government inspector is interested in whether or not the proportion of seeds germinating is living up to the company's claim. He randomly selects a sample of 200 seeds from a large shipment and tests the sample for percentage of germination. If 155 of the 200 seeds germinate, then the calculated value of the test statistic used to test the hypothesis of interest is?


Paper#60814 | Written in 18-Jul-2015

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