Class Note for PUBHLTH 540 at UMass(3)
Class Note for PUBHLTH 540 at UMass(3)
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This 2 page Class Notes was uploaded by an elite notetaker on Friday February 6, 2015. The Class Notes belongs to a course at University of Massachusetts taught by a professor in Fall. Since its upload, it has received 15 views.
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Date Created: 02/06/15
Puleth 540 Introductory Biostatistics Page 1 of 2 Unit 7 Hypothesis Testing Week 11 Practice Problems This Assignment is optional read You all get full credit no matter what 1 Betore you begin This exercise is a two sample ndependent groups t test of equality of means where the variances are unknown but assumed equal See lecture notes for Unit 7Hypothesis Testing pp 4043 See text pp 304308 An independent testing agency was hired prior to the November 2004 election to study whether or not the work output is different for construction workers employed by the state and receiving prevailing wages versus construction workers in the private sector who are paid rates determined by the free market A sample of 100 private sector workers reveals an average output of 743 parts per hour with a sample standard deviation of 16 parts per hour A sample of 100 state workers reveals an average output of 697 parts per hour with a standard deviation of 18 parts per hour You may assume equality ofvariances in your work a Is there evidence of a difference in productivity at the 010 level of signi cance b Is there evidence of a difference in productivity at the 005 level of significance c What is the achieved level of significance 2 Betore you begin This exercise is a continuation of the setting in Exercise 1 For the data in Exercise 1 what level of significance is achieved by the data if the sample means and sample standard deviations are unchanged but the within group sample sizes are a both equal to 10 b both equal to 200 c Comment on the role of sample size in the probability of a type I error ZWk117practicedoc Puleth 540 Introductory Biostatistics Page 2 of 2 3 Betore you begin This exercise is a paired data setting ttest of equality of means See lecture notes for Unit 7Hyp0thesis Testing pp 3639 See text pp 298302 Halcion is a sleeping pill that is relatively rapidly metabolized by the body and therefore having fewer hangover effects the next morning compared to other sleeping pills Opponents of Halcion argue that because this agent is so rapidly metabolized by the body patients do not sleep as long with this drug as with Dalmane Data on 10 insomniacs each of whom took Dalmane on one occasion and Halcion on a second is collected The variable measured is number of hours of sleep Number of Hours Sleep with Patient Dalmane Halcion 1 458 397 2 519 488 3 394 409 4 632 587 5 768 693 6 348 400 7 572 508 8 704 695 9 527 496 10 584 513 Do these data suggest that Halcion is not as effective as Dalmane with respect to number of hours of sleep Carry out an appropriate statistical test and interpret your ndings 4 Betore you begin This exercise is a con dence interval for the mean of the di erence in the paired data setting See lecture notesfar Unit 6Estimati0n pp 4043 See textpp 303 For the Halcion versus Dalmane data in Exercise 3 construct a 99 con dence interval estimate of discrepancy in the efflcacies of the two drugs Compare this to the acceptance region that would have been obtained had you constructed a statistical test with type I error prespecifled at 001 ZWk117practicedoc
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