In a study at West Virginia University Hospital, researchers investigated smoking behavior of cancer patients to create a program to help patients stop smoking. They published the results in Smoking Behaviors Among Cancer Survivors (January 2009 issue of the Journal of Oncology Practice.) In this study, the researchers sent a 22-item survey to 1,000 cancer patients. They collected demographic information (age, sex, ethnicity, zip code, level of education), clinical and smoking history, and information about quitting smoking. Which best describes the type of study? 0 An observational study comparing two populations 0 An experiment comparing two treatments In March 2015, the Public Policy Institute of California (PPIC) surveyed 7,525 likely voters living in California. In the survey, respondents were asked about global warming. PPIC researchers are interested in the difference in viewpoints across racial/ethnic groups. PPIC results show that 75% of Latinos view global warming as a serious problem, and 46% of whites view global warming as a serious problem. Using the data from the survey, we calculate the sample difference in global warming viewpoints for Latino respondents and white respondents to be 29% = 0.29. Researchers can use the 29% sample difference to draw a conclusion about which populations? O Latinos and whites who live in California and are concerned about global warming O Latinos and whites living in California who are likely to vote 0 Latinos and whites living in the United States who are likely voters O Latinos and whites who live in California In a January 2017 Washington Post-ABC News poll, respondents were asked "There is a proposal to offer nearly 140 billion dollars in tax cuts for private companies if they pay to build new roads, bridges and transportation projects. The companies then could charge tolls for people to use these roads, bridges and transportation. Do you support or oppose this proposal? Do you feel that way strongly or somewhat?" Of the 1005 people polled, 66 percent of those surveyed said they oppose the above proposal. Only 29 percent of the 1,005 people polled said they would support that plan, with 11 percent saying they backed it strongly and 18 percent saying they were somewhat supportive. Which best describes the goal of this study? C] Establish a cause-and-effect relationship between two categorical variables C] Test a claim or make an estimate about a population proportion C] Compare proportions from two populations Gardeners on the west coast of the United States are investigating the difference in survival rates of two flowering plants in drought climates. Plant A has a survival rate of 0.67 and plant B has a survival rate of 0.48. The standard error of the difference in proportions is 0.097. Which of the following is the margin of error for a 99% confidence interval? 0 0.250 O 0.190 O 0.160 O 0.097 In the article "Attitudes About Marijuana and Political Views" (Psychological Reports, 1973), researchers reported on the use of cannabis by liberals and conservatives during the 1970s. To test the claim (at 1% significance) that the proportion of voters who smoked cannabis frequently was lower among conservatives, the hypotheses were Ho : p1 - p2 = 0 (p1 = p2) Ha : p1 - p2 = 0 (p1 p2 Suppose that the P-value is 0.21. What type of error is possible? 0 Type II error: the evidence leads us to fail to reject the null hypothesis when the alternative hypothesis is true. 0 Type II error: the evidence leads us to tail to reject the null hypothesis when it is true. 0 Type I error: the evidence leads us to reject the null hypothesis when it was actually false. 0 Type I error: the evidence leads us to reject the null hypothesis, but it is actually true. In March 2015, the Public Policy Institute of California (PPIC) surveyed 7,525 likely voters living in California. A strong majority of Californians support the president's executive order on immigration. The 90% confidence interval for the difference in proportions of Californians and all U.S. residents who support the executive order on immigration is (0.163, 0.196). Which of the following conclusions about the confidence interval is most appropriate? Q We are 90% confident that the difference in the proportions of Californians and all U.S. residents who support the executive order on immigration is between 0.163 and 0.196. Q There is a 90% chance that the difference in the proportions of Californians and all U.S. residents who support the executive order on immigration is between 0.163 and 0.196. O 90% of the time the difference in support between Californians and all US. residents for the executive order on immigration is between 0.163 and 0.196. Previous studies suggest that use of nicotine-replacement therapies and antidepressants can help people stop smoking. The New England Journal of Medicine published the results of a double-blind, placebo-controlled experiment to study the effect of nicotine patches and the antidepressant bupropion on quitting smoking. The target for quitting smoking was the 8th day of the experiment. In this experiment researchers randomly assigned smokers to treatments. Of the 160 smokers taking a placebo, 25 stopped smoking by the 8th day. Of the 244 smokers taking only the antidepressant buproprion, 74 stopped smoking by the 8th day. Researchers calculated the 99% confidence interval to estimate the treatment effect of buproprion. What does "99% confident" mean? If the researchers repeat this experiment many times, there is a 99% chance that the true treatment effect of buproprion will be in the 99% interval reported by the researchers. If the researchers repeat this experiment many times and calculate a 99% confidence interval each time, 99% of these confidence intervals will contain the true treatment effect. O Q There is a 99% chance that the buproprion treatment is effective