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The article “HIV-positive Smokers Considering Quitting: Differences by Race/Ethnicity” (E. Lloyd-Richardson. C. Stanton, et al., Am J Health Behav, 2008:3–15) reported that in a group of 230 European-American HIV-positive smokers, 102 of them had used a nicotine patch to try to quit smoking, and in a group of 72 Hispanic-American HIV-positive smokers, 20 had used a nicotine patch. Can you conclude that the proportion of patch users is greater among European-Americans?
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- Colonoscopy is a medical procedure that is designed to find and remove precancerous lesions in the colon before they become cancerous. The article “Association of Colonoscopy and Death from Colorectal Cancer” (N. Baxter, M. Goldwasser, et al., Annals of Internal Medicine, 2009:1–8) reports that in a sample of 10,292 people diagnosed with colorectal cancer, 7.0% had previously had a colonoscopy, and in a sample of 51,460 people without colorectal cancer, 9.8% had previously had a colonoscopy. Can you conclude that the percentage of people who have had colonoscopies is greater in those without colorectal cancer?arrow_forwardIn low-speed crash tests of five cars, the repair costs were computed for a factory authorizedrepair and an independent repair workshop. The results are listed in Table 2. Is there sufficientevidence to support the claim that the independent workshop has lower repair costs? Use a 0.01significance level.Table 2 car 1 2 3 4 5 authorized repair centre X1 RM797 RM571 RM904 RM1147 RM418 independent workshop X2 RM523 RM488 RM875 RM911 RM297 D=X1 - X2 274 83 29 236 121 D2 = (X1 -X2)2 75076 6889 841 55696 14641arrow_forwardIn a study of whether taking a garlic supplement reduces the risk of getting a cold, participants were assigned to either a garlic supplement group or to a group that did not take a garlic supplement.† Based on the study, it was concluded that the proportion of people taking a garlic supplement who get a cold is lower than the proportion of those not taking a garlic supplement who get a cold. Do you think that the study was conducted in a reasonable way? What additional information would you want in order to evaluate this study? (Select all that apply.) A) whether the patients knew which treatment they were receiving B) whether the patients were randomly assigned to the treatments C) whether the patient's last name started with A through M D) whether the patient's cold lasted more than a week E) whether the experiment was conducted on a sufficient number of patients so that the differences observed could not be attributed to chancearrow_forward
- Three experiments investigating the relation between need for cognitive closure and persuasion were reported in “Motivated Resistance and Openness to Persuasion in the Presence or Absence of Prior Information,” by A. W. Kruglanski (Journal of Personality and Social Psychology, Vol. 65, No. 5, pp. 861–874). Part of the study involved administering a “need for closure scale” to a group of students enrolled in an introductory psychology course. The “need for closure scale” has scores ranging from 101 to 201. For the 73 students in the highest quartile of the distribution, the mean score was 178.70 . Assume a population standard deviation of 7.81. These students were all classified as high on their need for closure. Assume that the 73 students represent a random sample of all students who are classified as high on their need for closure. Find a 95% confidence interval for the population mean score on the “need for closure scale” for all students with a high need for closurearrow_forwardThe American Society for Microbiology (ASM) and the Soap and Detergent Association (SDA) jointly commissioned two separate studies during 2007, both of which were conducted by Harris Interactive. In one of the studies, 1001 adults were interviewed by telephone and asked about their hand-washing habits. In the other study, the hand-washing behavior of 6076 adults was inconspicuously observed within public restrooms in four U.S. cities. Address the following: a. In the telephone interviews, 921 of the adults said they always wash their hands in public restrooms. Use this result to obtain a point estimate for the proportion of adults who say they always wash their hands in public restrooms. b. Verify that the requirements for constructing a confidence interval for p from part (a) are satisfied. c. Using the results from the telephone interviews, construct and interpret a 95% confidence interval for the proportion of adults who say they always wash their hands in public restrooms. d. Is it…arrow_forwardTo determine current attitudes of parents concerning whether or not teachers should take a mandatory COVID-19 test to teach at schools, a survey was conducted in four public schools. The following table gives the attitudes of 550 parents surveyed: School 1 School 2 School 3 School 4In Favor 65 66 40 34Oppose 42 30 33 42No Opinion 93 54 27 24 Test whether there is an association between the School and the attitude towards mandatory COVID19 test at 1% level of significance.arrow_forward
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