Influencing Voters When getting voters to support a candidate in an election, is there a difference between a recorded phone call from the candidate or a flyer about the candidate sent through the mail? A sample of 400 voters is randomly divided into two groups of 200 each, with one group getting the phone call and one group getting the flyer. The voters are then contacted to see if they plan to vote for the candidate in question. We wish to see if there is evidence that the proportions of support are different between the two methods of campaigning. Sample A Will vote for Candidate Will not vote for Candidate Phone Call 113 87 Flyer 97 103 Table 1: Sample A: Is a phone call or a flyer more effective? Sample B Will vote for Candidate Will not vote for Candidate Phone Call 150 50 Flyer 83 117 Table 2: Sample B: Is a phone call or a flyer more effective? (a) State the null and alternative hypotheses. Let group 1 be the supporters of Candidate A after a phone call and let group 2 be the supporters of Candidate A after a flyer. :: :: /2 : p :: P1 : P2 :: :: P2 Ho: 1 vs Ha: ! eTextbook and Media Hint(b) Possible sample results are shown in Table 1. Compute the two sample proportions: p,, the proportion of voters getting the phone call who say they will vote for the candidate, and p2 , the proportion of voters getting the flyer who say they will vote for the candidate. Enter the exact answers. PI = P2 = i Is there a difference in the sample proportions? eTextbook and Media Hint (c) A different set of possible sample results are shown in Table 2. Compute the same two sample proportions for this table. Enter the exact answers. P1 = P2 = i eTextbook and Media Hint (d) Which of the two samples seems to offer stronger evidence of a difference in effectiveness between the two campaign methods? O Sample A O Sample BThe figure below shows a randomization distribution based on 1000 simulated samples for testing Ho : p = 0.3 vs Ha : p 0.05." Let group 1 be males and group 2 be females. Sforza C, Grandi G, De Menezes M, Tartaglia GM, Ferrario VF, "Age- and sex-related changes in the normal human external nose", Forensic Science International, 2011 Jan 30;204(1-3):205.e1-9. (a) State the hypotheses. : P1 : P2 H p : 22 : p : P1 P2 Ho: vs Ha:(b) Give the formal decision using a 5 % significance level. O Reject Ho. O Do not reject Ho. eTextbook and Media Hint (c) Interpret the conclusion in context. O We have evidence that males and females have the same average nasal tip angle. O We do not have evidence that males and females have the same average nasal tip angle. O We have evidence that there is a difference between males and females in average nasal tip angle. O We do not have evidence that there is a difference between males and females in average nasal tip angle