Concept explainers
Smoking Cessation In a 2018 study reported in The New England Journal of Medicine, Halpern et al. randomly assigned smokers to one of five groups, including four smoking cessation interventions and usual care. Usual care consisted of access to information regarding the benefits of smoking cessation and to a motivational text-messaging service. The four interventions consisted of usual care plus one of the following: free cessation aids such as nicotine-replacement therapy or pharmacotherapy, free e-cigarettes, free cessation aids plus
a. Is this study an observational study or a controlled experiment? Explain.
b. Identify the treatment and response variables.
c. Can a cause-and-effect conclusion be drawn from this study? Why or why not?
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Introductory Statistics
- A research article describes a study that investigated the relationship between depression and chocolate consumption. Participants in the study were 931 adults who were not currently taking medication for depression. These participants were screened for depression using a widely used screening test. The participants were then divided into two samples based on their test score. One sample consisted of people who screened positive for depression, and the other sample consisted of people who did not screen positive for depression. Each of the study participants also completed a food frequency survey. The researchers believed that the two samples were representative of the two populations of interest—adults who would screen positive for depression and adults who would not screen positive. The paper reported that the mean number of servings per month of chocolate for the sample of people that screened positive for depression was 8.37, and the sample standard deviation was 14.85. For the…arrow_forwardA study prospectively examined whether sleep-disordered breathing was associated with an increased risk of death from any cause in a cohort of 600 adults participating in the Sleep Heart Health Study. Study participants were classified into four groups depending on the extent of their sleep-disordered breathing (none, mild, moderate, or severe). The counts of deaths over the course of the study are reported for each group in the following two-way table. Mild Severe 100 Death No Death Total None 40 100 140 40 100 140 Moderate 20 100 120 Total 200 400 600 100 200 We want to know whether the study findings give evidence of a significant difference of the number of deaths between the different groups. Set up the alternative hypothesis (H, : The distribution of the categorical variable is not as given by the null hypothesis (lack of fit) At least ones of the means is different from the others O The two categorical variables are dependent The distribution of the categorical variable is not…arrow_forwardIn studies examining the effect of humor on interpersonal attractions, McGee and Shevlin (2009) found that an individual’s sense of humor had a significant effect on how the individual was perceived by others. In one part of the study, female college students were given brief descriptions of a potential romantic partner. The fictitious male was described positively as being single and ambitious and having good job prospects. For one group of participants, the description also said that he had a great sense of humor. For another group, it said that he has no sense of humor. After reading the description, each participant was asked to rate the attractiveness of the man on a seven-point scale from 1 (very unattractive) to 7 (very attractive). A score of 4 indicates a neutral rating. The females who read the “great sense of humor” description gave the potential partner an average attractiveness score of M = 4.53 with a standard deviation of s = 1.04. If the sample consisted of n = 16…arrow_forward
- In a study examining the effect of humor on interpersonal attractions, McGee and Shevlin (2009) found that a man’s sense of humor had a significant effect on how he was perceived by women. In the study, female college students were given brief descriptions of a potential romantic partner and then rated the attractiveness of the male on a scale from 1 (low) to 7 (high). The fictitious male was described positively as being single, ambitious, and having good job prospects. In one condition, the description also said that he had a great sense of humor. The results showed that the description was rated significantly higher when “a sense of humor” was included. To examine this effect further, a researcher selected a sample of n = 16 college males and asked them to read a brief description of a female and then rate the attractiveness of the woman in the description. The description had been used in previous research but was modified by adding a statement describing a good sense of humor.…arrow_forwardIn a study examining the effect of humor on interpersonal attractions, McGee and Shevlin (2009) found that a man’s sense of humor had a significant effect on how he was perceived by women. In the study, female college students were given brief descriptions of a potential romantic partner and then rated the attractiveness of the male on a scale from 1 (low) to 7 (high). The fictitious male was described positively as being single, ambitious, and having good job prospects. In one condition, the description also said that he had a great sense of humor. The results showed that the description was rated significantly higher when “a sense of humor” was included. To examine this effect further, a researcher selected a sample of n = 16 college males and asked them to read a brief description of a female and then rate the attractiveness of the woman in the description. The description had been used in previous research but was modified by adding a statement describing a good sense of humor.…arrow_forwardTeen smoking, part I A Vermont study published by the American Academy of Pediatrics examined parental in-fluence on teenagers’ decisions to smoke. A group of stu-dents who had never smoked were questioned about their parents’ attitudes toward smoking. These students werequestioned again two years later to see if they had started smoking. The researchers found that, among the 284 stu-dents who indicated that their parents disapproved of kids smoking, 54 had become established smokers. Among the 41 students who initially said their parents were le-nient about smoking, 11 became smokers. Do these data provide strong evidence that parental attitude influencesteenagers’ decisions about smoking?a) What kind of design did the researchers use?b) Write appropriate hypotheses.c) Are the assumptions and conditions necessary forinference satisfied?d) Test the hypothesis and state your conclusion.e) Explain in this context what your P-value means.f) If that conclusion is actually wrong, which type…arrow_forward
- As part of a long-term study of individuals 65 years of age or older, sociologists and physicians at the Wentworth Medical Center in upstate New York investigated the relationship between geographic location and depression. A sample of 60 individuals, all in reasonably good health, was selected; 20 individuals were residents of Florida, 20 were residents of New York, and 20 were residents of North Carolina. Each of the individuals sampled was given a standardized test to measure depression. Higher test scores indicate higher levels of depression. A second part of the study considered the relationship between geographic location and depression for individuals 65 years of age or older who had a chronic health condition such as arthritis, hypertension, and/or heart ailment. A sample of 60 individuals with such conditions was identified. Again, 20 were residents of Florida, 20 were residents of New York, and 20 were residents of North Carolina. Prepare a managerial report that summarizes…arrow_forwardIndividuals with strong religious beliefs often turn to their faith to cope with stressful life events. Relying on God's love and caring is referred to as positive religious coping. Andrea Phelps and her colleagues studied the relationship between positive religious coping and the type of care received by terminally ill cancer patients. Most of the patients in the study were Christian. [Source: Phelps, A. et al., "Religious coping and use of intensive life-prolonging care near death in patients with advanced cancer." Journal of the American Medical Association, 301 (2009): 1140-1147.] Suppose another researcher conducts a similar study but uses a sample of patients whose religious traditions are more varied than the patients in the Phelps study. He samples 400 terminally ill patients to see whether their practicing a religion is related to how likely they are to seek intensive life-prolonging care. The following table shows the results of the study. Observed Frequencies Seeks Intensive…arrow_forwardA study prospectively examined whether sleep-disordered breathing was associated with an increased risk of death from any cause in a cohort of 600 adults participating in the Sleep Heart Health Study. Study participants were classified into four groups depending on the extent of their sleep-disordered breathing (none, mild, moderate, or severe). The counts of deaths over the course of the study are reported for each group in the following two-way table. Mild Death No Death Total None 40 100 140 40 100 140 Moderate 20 100 120 Severe 100 100 200 Total 200 400 600 We want to know whether the study findings give evidence of a significant difference of the number of deaths between the different groups. Compute the p -value and make a decision O The p-value 0.25. fail to reject the null hypothesis O The p-value is between 0.04 and 0.05, reject the null hypothesisarrow_forward
- A study prospectively examined whether sleep-disordered breathing was associated with an increased risk of death from any cause in a cohort of 600 adults participating in the Sleep Heart Health Study. Study participants were classified into four groups depending on the extent of their sleep-disordered breathing (none, mild, moderate, or severe). The counts of deaths over the course of the study are reported for each group in the following two-way table. Death No Death Total None 40 100 140 Mild 40 100 140 Moderate 20 100 120 Severe 100 100 200 Total 200 400 600 We want to know whether the study findings give evidence of a significant difference of the number of deaths between the different groups. The observed test statistic is 3.610 42.857 5.476 8.075arrow_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
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