Concept explainers
Putting It Together: Smoking Cessation Study Researchers Havar Brendryen and Pal Kraft conducted a study in which 396 subjects were randomly assigned to either an experimental smoking cessation program or control group. The experimental program consisted of the Internet and phone-based Happy Ending Intervention, which lasted 54 weeks and consisted of more than 400 contacts by e-mail, web pages, interactive voice response, and short message service (SMS) technology. The control group received a self-help booklet. Both groups were offered free nicotine replacement therapy. Abstinence was defined as “not even a puff of smoke, for the last 7 days.” and assessed by means of Internet surveys or telephone interviews. The response variable was abstinence after 12 months. Of the participants in the experimental program. 22.3% reported abstinence; of the participants in the control group, 13.1% reported abstinence.
Source: “Happy Ending: A Randomized Controlled Trial of a Digital Multi/Media Smoking Cessation intervention.” Havar Brendryen and Pal Kraff. Addiciton 103(3):478–484, 2008.
- a. What type of experimental design is this?
- b. What is the treatment? How many levels does it have?
- c. What is the response variable?
- d. What are the statistics reported by the authors?
- e. An odds ratio is the ratio of the odds of an
event occurring in one group to the odds of it occurring in another group. These groups might be men and women, an experimental group and a control group, or any other dichotomous classification. If the probabilities of the event in each of the groups are p (first group) and q (second group), then the odds ratio is
An odds ratio of 1 indicates that the condition or event understudy is equally likely in both groups. An odds ratio greater than 1 indicates that the condition or event is more likely in the first group. And an odds ratio less than 1 indicates that the condition or event is less likely in the first group. The odds ratio must be greater than or equal to zero. As the odds of the first group approach zero, the odds ratio approaches zero. As the odds of the second group approach zero, the odds ratio approaches positive infinity. Verify that the odds ratio for this study is 1.90. What does this mean?
- f. The authors of the study reported a 95% confidence interval for the odds ratio to be lower bound: 1.12 and upper bound 3.26. Interpret this result.
- g. Write a conclusion that generalizes the results of this study to the population of all smokers.
Want to see the full answer?
Check out a sample textbook solutionChapter 9 Solutions
Fundamentals of Statistics (5th Edition)
- What is meant by the sample space of an experiment?arrow_forwardWhat is an experiment?arrow_forwardResearchers studied a group of 30 “self-designated worriers” (i.e. individuals who reported spending at least 10% of the day worrying) and who were over the age of 70 (mean age of 78.1). The researcher randomly assigned the worriers into three groups. For the next four weeks, each group would experience a different approach to handling worry. One group engaged in a worry-focus discussion group. The second group members enjoyed individual therapy. The third group went for daily walks in the park. Data was collected, analyzed, and interpreted. Write a valid one sentence hypothesis statement using proper form of the above research design.arrow_forward
- The Pew Research Center Internet Project, conducted on the 25th anniversary of the Internet, involved a survey of 857 Internet users (Pew Research Center website, April 1, 2014). It provided a variety of statistics on Internet users. For instance, in 2014, 87% of American adults were Internet users. In 1995 only 14% of American adults used the Internet.a. The sample survey showed that 90% of respondents said the Internet has been a good thing for them personally. Develop a 95% confidence interval for the proportion of respondents who say the Internet has been a good thing for them personally.b. The sample survey showed that 67% of Internet users said the Internet has generally strengthened their relationship with family and friends. Develop a 95% confidence interval for the proportion of respondents who say the Internet has strengthened their relationship with family and friends.c. Fifty-six percent of Internet users have seen an online group come together to help a person or community…arrow_forwardTobacco companies have actively attempted to remake their public image by launching a youth smoking prevention advertisement campaign. Melanie Wakefield (a professor of applied psychology and researcher at the Center for Behavioral Research in Cancer in Victoria, Australia) and her colleagues conducted a study to assess the relation between exposure to tobacco companies' youth smoking prevention advertising and youth smoking-related beliefs, intentions, and behaviors. You use Professor Wakefield's research to design an experiment with two groups of middle school students from Vietnam. You show the tobacco company's youth smoking prevention ads to one of the groups of students every day for a week at the beginning of their math class. After the week, you assess the groups on the degree to which the students approve/disapprove of teens smoking, using a 5-point Likert scale. You do not have a prediction about the effect of the ads, as they are supposed to prevent smoking, but Professor…arrow_forwardThe Health Behaviour in School-Aged Children (HSBC) network collects data on various behaviors of preteen and teenage children. In 2006, the HSBC network surveyed a randomly selected sample of 638 preteen and teenage boys in Greenland to determine what proportion of students were bullied at least twice per month in the previous few months. In the sample, 147 students were bullied at least twice per month, and 491 students were bullied less than twice per month. The HSBC network wants to construct a 95% confidence interval for p, the proportion of preteen and teenage boys who are bullied at least twice per month in Greenland. Have the requirements for a large-sample z-confidence interval been met? Mark all of the following requirements that have been met with yes, and the requirements that have not been met with no. O O The sample is a simple random sample. The parameter of interest is categorical with two possible outcomes, which are considered success and failure. When the sample…arrow_forward
- Seattle Grace Medical Center. As part of a long-term study of individuals 65 years of age or older, doctors at the Seattle Grace Medical Center in Washington state investigated the relationship between state of residence and depression. A sample of 60 individuals, all in reasonably good health, was selected; 20 individuals were residents of Texas, 20 were residents of Washington state, and 20 were residents of South Carolina. Each of the individuals sampled was given a standardized test to measure depression. The data collected follow; higher test scores indicate higher levels of depression. These data are contained in the attached data file SeattleGrace1. A second part of the study considered the relationship between state of residence and depression for individuals 65 years of age or older who had a chronic health condition such as diabetes and/or high blood pressure. A sample of 60 individuals with such conditions was identified. Again, 20 were residents of Texas, 20 were residents…arrow_forwardSeattle Grace Medical Center. As part of a long-term study of individuals 65 years of age or older, doctors at the Seattle Grace Medical Center in Washington state investigated the relationship between state of residence and depression. A sample of 60 individuals, all in reasonably good health, was selected; 20 individuals were residents of Texas, 20 were residents of Washington state, and 20 were residents of South Carolina. Each of the individuals sampled was given a standardized test to measure depression. The data collected follow; higher test scores indicate higher levels of depression. These data are contained in the attached data file SeattleGrace1. A second part of the study considered the relationship between state of residence and depression for individuals 65 years of age or older who had a chronic health condition such as diabetes and/or high blood pressure. A sample of 60 individuals with such conditions was identified. Again, 20 were residents of Texas, 20 were residents…arrow_forwardSeattle Grace Medical Center. As part of a long-term study of individuals 65 years of age or older, doctors at the Seattle Grace Medical Center in Washington state investigated the relationship between state of residence and depression. A sample of 60 individuals, all in reasonably good health, was selected; 20 individuals were residents of Texas, 20 were residents of Washington state, and 20 were residents of South Carolina. Each of the individuals sampled was given a standardized test to measure depression. The data collected follow; higher test scores indicate higher levels of depression. These data are contained in the attached data file SeattleGrace1. A second part of the study considered the relationship between state of residence and depression for individuals 65 years of age or older who had a chronic health condition such as diabetes and/or high blood pressure. A sample of 60 individuals with such conditions was identified. Again, 20 were residents of Texas, 20 were residents…arrow_forward
- According to the February 2008 Federal Trade Commission report on consumer fraud and identity theft, 23% of all complaints in 2007 were for identity theft. In that year, assume some state had 454 complaints of identity theft out of 1660 consumer complaints. Do these data provide enough evidence to show that the state had a higher proportion of identity theft than 23%? Test at the 10% level.arrow_forwardThe District of Columbia Opportunity Scholarship Program was created by Congress to provide tuition vouchers to low-income parents who want their child to attend a private school. In 2012–2014, a treatment group of 995 students were randomly selected to receive a tuition voucher, while a control group of 776 students did not receive vouchers. One year later, the students were given a standardized reading test. The average score of the students in the treatment group was 601.78 with a standard deviation of 52.65; the average score of the control group was 605.78 with a standard deviation of 55.73. At the level of significance alpha = 0.01, do we have enough evidence to conclude that the average reading score of students who receive a tuition voucher to attend private school is lower than the average reading score of students who do not receive a tuition voucher?arrow_forwardMost alpine skiers and snowboarders do not use helmets. Do helmetsreduce the risk of head injuries? A study in Norway compared skiers and snowboarders who suffered head injuries with a control group who were not injured. Of 578 injured subjects, 96 had worn a helmet. Of the 2992 in the control group, 656 wore helmets. Is helmet use less common among skiers and snowboarders who have head injuries?arrow_forward
- Holt Mcdougal Larson Pre-algebra: Student Edition...AlgebraISBN:9780547587776Author:HOLT MCDOUGALPublisher:HOLT MCDOUGALGlencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw HillCollege Algebra (MindTap Course List)AlgebraISBN:9781305652231Author:R. David Gustafson, Jeff HughesPublisher:Cengage Learning