Concept explainers
Efficacy of e-Cigs Do electronic cigarettes assist in helping individuals quit smoking? Researchers found 300 current smokers to volunteer for a study in which each was randomly assigned to one of three treatment groups. Group 1 received an electronic cigarette (e-cig) in which each cartridge contained 7.2 mg of nicotine, Group 2 received an e-cig that contained 5.4 mg of nicotine, and Group 3 received an e-cig that contained no nicotine. The subjects did not know which group they were assigned. During the course of the 52-week intervention, subjects dropped out of the study. At the end of the study 65 subjects remained in Group 1,63 in Group 2, and 55 in Group 3. After 52 weeks, it was determined via questionnaire whether the subject quit smoking entirely. Results of the study are presented in the following table.
Source: Caponnetto P, Campagna D, Cibella F, Morjaria JB, Caruso M, et al. (2013) Efficiency and Safety of an electronic cigarette (ECLAT) as Tobacco Cigarettes Substitute: A Prospective 12-Month Randomized Control Design Study. PLoS ONE 8(6): e66317.
doi:10.1371/journal.pone.0066317
- a. What type of experimental design was used in this study?
- b. Researchers wanted to know whether electronic cigarettes may be used to help individuals abstain from cigarette smoking. What is the response variable? Is it qualitative or quantitative?
- c. To what population do the results of this study apply?
- d. State the null and alternative hypotheses.
- e. Does the evidence suggest e-cigs are effective in helping individuals abstain from cigarette smoking?
- f. Draw a conditional bar graph by group. Explain what the graph suggests.
- g. Write a conclusion for this hypothesis test.
Want to see the full answer?
Check out a sample textbook solutionChapter 12 Solutions
Fundamentals of Statistics (5th Edition)
- Car Window Skin Cancer? A study suggests that exposure to UV rays through the car window may increase the risk of skin cancer. The study reviewed the records of all 1050 skin cancer patients referred to the St. Louis University Cancer Center in 2004. Of the 42 patients with melanoma, the cancer occurred on the left side of the body in 31 patients and on the right side in the other 11. A. Is this an experiment or an observational study? B. Of the patients with melanoma, what proportion had the cancer on the left side? Show what numbers you divide and give answer to 3 decimal places. C. A bootstrap 95% confidence interval for the proportion of melanomas occurring on the left is 0.579 to 0.861. Clearly interpret the confidence interval in the context of the problem. D. Suppose the question of interest is whether melanomas are more likely to occur on the left side than on the right. That is, are over 50% of melanomas on the left side? Ho: p = 0.5 Ha: p > 0.5 Use the confidence interval…arrow_forwardIn an observational study it was found that people who had received the flu shot this year had better blood pressure readings, on average, than people who did not. Can it be claimed that the flu shot is the cause of the lower overall blood pressure? Why or why not?arrow_forwardPeople with headaches are randomly divided into two groups. One group gets pain medication, and the other does not. One hour later, the participants are asked about their pain. If it is an experimental study, what is the control group?arrow_forward
- A behavioral scientist investigated whether there is a significant difference in the percentages of men and women who purchase silver-colored cars. The scientist selected a random sample of 50 men and a random sample of 52 women who had recently purchased a new car. Of the men selected, 16 had purchased a silver-colored car. Of the women selected, 9 had purchased a silver-colored car. Which of the following is the most appropriate method for analyzing the results? A two-sample zz-test for the difference in population proportions A A two-sample zz-test for the difference in sample proportions B A one-sample zz-test for a sample proportion C A one-sample zz-test for a population proportion D A one-sample zz-test for a difference in sample proportionsarrow_forwardWhy is 14% of the questionnaires returned, which means the response rate is low?arrow_forward
- Glencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw HillHolt Mcdougal Larson Pre-algebra: Student Edition...AlgebraISBN:9780547587776Author:HOLT MCDOUGALPublisher:HOLT MCDOUGALCollege Algebra (MindTap Course List)AlgebraISBN:9781305652231Author:R. David Gustafson, Jeff HughesPublisher:Cengage Learning
- Big Ideas Math A Bridge To Success Algebra 1: Stu...AlgebraISBN:9781680331141Author:HOUGHTON MIFFLIN HARCOURTPublisher:Houghton Mifflin Harcourt