STA 210 Chapter 7 Homework

For the next 3 question please read the article on pages 148 and 149 in your textbook. Question: a. What is the ratio of a 95% margin of error to an 80% margin of error for the true proportion of all Americans who believe that the reform package will prohibit insurers from denying coverage to people? 0.020 0.014 1.430 0.050

1.430

Some Pay Saves Day There were 577 non-respondents still remaining after the Phase II attempt. In Phase III, these 577 were contacted again and asked to complete the survey. This time, however, the remaining non-respondents were randomly divided into two groups: one would receive no compensation for completion, while the other would receive $30 for completion. Here is what the researchers found: Incentive GroupNumber of RespondentsNumber of Non-RespondentsNF1 ($0)98190NF2 ($30)135154 What pair of fractions from the table would be used to support or refute a claim that incentives matter when conducting follow-ups for survey completion? 98/190 and 135/154 135/289 and 98/288 98/233 and 190/344 135/233 and 154/344

135/289 and 98/288

What two fractions produced from the table would be used to support or refute a claim that a high incentive is more effective than a low incentive at achieving early completion of a survey? 404/471 and 391/471 138/404 and 120/391 138/266 and 120/271 404/873 and 391/873

138/404 and 120/391

Title: Question WordingAuthors: Pew Research CenterSource: http://www.people-press.org/methodology/questionnaire-design/question-wording/ (Links to an external site.) The Pew Research Center is one of the most prolific polling organizations operating today. The referenced article, provided by the Pew Research Center itself, is a short tutorial on the importance of question wording. Find the article, read it, and then answer the next two questions. Question: In the primary example provided, Americans were asked about the desirability of using military action to end Saddam Hussein's rule in Iraq. An altered version of that same question added the clause "even if it meant that U.S. forces might suffer thousands of casualties." What was the percentage drop in affirming answers? 35% 15% The article just says the percentage changed but doesn't say by how much. 25%

25%

Pay to PlayTitle: Efficacy of Incentives in Increasing Response RatesAuthors: Fahimi, M., Whitmore, R.W., Chromy, J.R., Siegel, P.H., & Cahalan, M.J. (2006). Source: Presented at Second International Conference on Telephone Survey Methodology, Miami, FL, https://www.rti.org/sites/default/files/resources/TSM2006_Fahimi-efficacy_paper.pdf (Links to an external site.) An internet search on the effects of incentives on increasing response rates will reveal a lot of research on the topic. One particular study conducted at the Research Triangle Institute in Raleigh-Durham, North Carolina, is particularly interesting. In Phase I of the study, 1,197 subjects were contacted and asked to complete a survey. However, those subjects were randomly split into three subgroups. Subjects in the first group were not offered any monetary reward for early completion of the survey. Subjects in the second were offered $20 for early completion, and those in the third group were offered $30 for early completion. Here is what the researcher found. Use this data for the next 2 questions. Incentive Group (Early Response)Number of RespondentsNumber of Non-RespondentsGroup 1 ($0)66336Group 2 ($20)120271Group 3 ($30)138266Total324873 Question: What two fractions produced from the table would be used to support or refute a claim that incentives matter for early completion of a survey? 402/873 and 795/873 336/402 and 537/795 66/402 and 258/795 66/336 and 258/537

66/402 and 258/795

The article lists several tips for survey construction. Which of the following four statements are the two "important things to consider in crafting survey questions" that the article mentions?A. "Ask questions that are clear and specific and that each respondent will be able to answer."B. "Try to limit the number of response options in an effort to elicit more truthful answers."C. "If possible, make sure an interviewer is present, in an attempt to reduce social desirability bias."D. "Ask only one question at a time." A and D B and D B and C A and B

A and D

If the sample had truly been a random sample of all university and college students, what percentage of women would you expect to have been in the sample? About 50% About 5% About 34% About 66%

About 50%

What is meant by the following statement that appears in the Methodology section?"Because the sample is based on those who agreed to participate in the Harris Interactive panel, no estimates of theoretical sampling error can be calculated." In the complete absence of sampling errors, the MOE would still have been useful to have as a way of summarizing selection bias. Even if there were significant sampling error, the MOE would be suspect because of all the errors due to how the health-reform questions were designed. In the complete absence of non-sampling error, the MOE would have been appropriate for this survey. Even if there were no non-sampling errors, the MOE is suspect because the data are based on a sample from those who agreed to participate.

Even if there were no non-sampling errors, the MOE is suspect because the data are based on a sample from those who agreed to participate.

That's Getting Personal Please use the information below to answer the next 2 questions Title: Playboy Survey Asks College Students about Sex LivesAuthor: Marilyn KingSource: State News, September 17, 2009, http://www. statenews.com/index.php/article/2009/09/playboy_survey_asks_college_students_about_sex_lives Conducted at Playboy.com, the survey asked 5,000 U.S. university and college students about their sex lives. Of the respondents, 80% were male and 20% were female. One question asked the following:"Are you in a nude picture on someone's camera phone?" Thirty-four percent said "yes." Question: Other samples of 5,000 people, asked the same question, would not produce a sample percentage of 34%. What is this kind of variability called? Margin of error variability Sampling variability Non-response variability Non-sampling variability

Sampling variability

What is meant by the following statement that appears in the Methodology section? "Therefore, Harris Interactive avoids the words' margin of error' as they are misleading." There are so many different kinds of non-sampling error that go into a survey, only one of which the MOE addresses. There are so many different kinds of error that go into a survey, only one being biased sampling error, which is what the MOE addresses. There are so many different kinds of error that go into a survey, only one being non-sampling error, which is what the MOE addresses. There are so many different kinds of error that go into a survey, only one being random sampling error, which is what the MOE addresses.

There are so many different kinds of error that go into a survey, only one being random sampling error, which is what the MOE addresses.