Concept explainers
Treating Carpal Tunnel Syndrome Carpal tunnel syndrome is a common wrist complaint resulting from a compressed nerve, and it is often the result of extended use of repetitive wrist movements, such as those associated with the use of a keyboard. In a randomized controlled trial, 73 patients were treated with surgery and 67 were found to have successful treatments. Among 83 patients treated with splints, 60 were found to have successful treatments (based on data from “Splinting vs Surgery in the Treatment of Carpal Tunnel Syndrome.” by Gerritsen et al., Journal of the American Medical Association, Vol. 288, No. 10). Use the accompanying StatCrunch display with a 0.01 significance level to test the claim that the success rate is better with surgery.
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- A migraine is a particularly painful type of headache, which patients sometimes wish to treat with acupuncture. To determine whether acupuncture relieves migraine pain, researchers conducted a randomized controlled study where 89 females diagnosed with migraine headaches were randomly assigned to one of two groups: treatment or control. 43 patients in the treatment group received acupuncture that is specifically designed to treat migraines. 46 patients in the control group received placebo acupuncture (needle insertion at non-acupoint locations). 24 hours after patients received acupuncture, they were asked if they were pain free. Results are summarized in the contingency table below (Allais, 2011).(round answers to 2 decimal places) Pain Free: Yes Pain Free: No Total Treatment 10 33 43 Control 2 44 46 Total 12 77 89 a) What percent of patients in the treatment group were pain free 24 hours after receiving acupuncture? %b) What percent of patients in the control…arrow_forwardA migraine is a particularly painful type of headache, which patients sometimes wish to treat with acupuncture. To determine whether acupuncture relieves migraine pain, researchers conducted a randomized controlled study where 98 females diagnosed with migraine headaches were randomly assigned to one of two groups: treatment or control. 45 patients in the treatment group received acupuncture that is specifically designed to treat migraines. 53 patients in the control group received placebo acupuncture (needle insertion at non-acupoint locations). 24 hours after patients received acupuncture, they were asked if they were pain free. Results are summarized in the contingency table below.(please round answers to within one hundredth of a percent) Pain Free: Yes Pain Free: No Total Treatment 13 32 45 Control 4 49 53 Total 17 81 98 a) What percent of patients in the treatment group were pain free 24 hours after receiving acupuncture? %b) What percent of patients in the…arrow_forwardThe results of a multicenter clinical trial to determine the safety and efficacy of the pancreatic lipase inhibitor, Xenical, was reported (Ingersoll, 1997). Xenical is used to block the absorption of dietary fat. The article reported that more than 4000 patients in the U.S. and Europe were randomized to receive Xenical or a placebo in a parallel groups study. After one year, 57% of those receiving Xenical had lost at least 5% of their body weight, as opposed to 31% of those receiving a placebo. Assume that exactly 4000 patients were in the study, and that 2000 were randomized to receive a placebo and 2000 received Xenical. Please Compute a 95% confidence interval for the “relative risk” of losing at least 5% of body weight for those receiving Xenical relative to those receiving placebo. Can the drug be considered effective?arrow_forward
- The article “Treadmill Exercise and Resistance Training in Patients With Peripheral Arterial Disease With and Without Intermittent Claudication. A Randomized Controlled Trial” (M. McDermott, P. Ades, et al., Journal of the American Medical Association, 2009:165–174) reported the results of a study to determine whether treadmill exercise could improve the walking ability of patients suffering from claudication, which is pain caused by insufficient blood flow to the muscles of the legs. A sample of 48 patients walked on a treadmill for six minutes every day. After six months, the mean distance walked in six minutes was 348 m, with a standard deviation of 80 m. For a control group of 46 patients who did not walk on a treadmill, the mean distance was 309 m with a standard deviation of 89 m. Find a 95% confidence interval for the difference in mean distance walked between the two groups of patients.arrow_forwardThe article “Treadmill Exercise and Resistance Training in Patients With Peripheral Arterial Disease With and Without Intermittent Claudication. A Randomized Controlled Trial” (M. McDermott, P. Ades, et al., Journal of the American Medical Association, 2009:165–174) reported the results of a study to determine whether treadmill exercise could improve the walking ability of patients suffering from claudication, which is pain caused by insufficient blood flow to the muscles of the legs. A sample of 48 patients walked on a treadmill for six minutes every day. After six months, the mean distance walked in six minutes was 348 meters, with a standard deviation of 80 m. For a control group of 46 patients who did not walk on a treadmill, the mean distance was 309 m with a standard deviation of 89 m. Can you conclude that the mean distance walked for patients using a treadmill is greater than the mean for the controls? Use the α = 0.05 level of significance.arrow_forwardA research group is interested in the association between vitamin E supplementation and a decreased risk for osteoporosis in a group of elderly women. The team randomly samples a group of women potentially enrolled in the study after a strict set of inclusion criteria have been met, and pairs each woman receiving the supplementation with two women receiving a placebo based on a number of characteristics such as BMI, education, and socio-economic status. The data compiled after 10 years of follow up were analyzed using conditional logistic regression. Which of the following methods to reduce confounding was not employed in the above scenario? Stratification Regression Restriction Matchingarrow_forward
- Lecturers at a university intend to see the effect of stress relief strategies such as deep breathing and relaxation techniques to the student performance in the final exam. For this reason, they assigned students of the same year in two different cohorts. More precisely, students in Cohort 1 did not do any relaxation techniques before the exam, while students in Cohort 2 performed a full range of the relaxation techniques approved by the British Psychological Society. The average mark of a random sample of 17 students from Cohort 1 was 61, with a standard deviation of 17, while the average mark of a random sample of 11 students from Cohort 2 was 67 with a standard deviation of 19. (a) Test whether the variances of marks for the two cohorts are the same at the 5% significance level. (b) Test the hypothesis that the average mark in the exam for Cohort 1 students isthe same as that for students of Cohort 2 at the 5% significance level. For this test, what is the p-value? (c) What…arrow_forwardLecturers at a university intend to see the effect of stress relief strategies such as deep breathing and relaxation techniques to the student performance in the final exam. For this reason, they assigned students of the same year in two different cohorts. More precisely, students in Cohort 1 did not do any relaxation techniques before the exam, while students in Cohort 2 performed a full range of the relaxation techniques approved by the British Psychological Society. The average mark of a random sample of 17 students from Cohort 1 was 61, with a standard deviation of 17, while the average mark of a random sample of 11 students from Cohort 2 was 67 with a standard deviation of 19. a) Calculate a 95% confidence interval for the difference in average marks in theexam for the two cohorts of students. Explain the meaning of the 95% confidence interval that you have calculated.arrow_forwardA study measuring the fatigue of air traffic controllers resulted in proposals for modficiation and redesign of the controllers' workstation. After consideration of several designs for the workstation, three specific alternatives are selected as having the best potential for reducing controller stress. The key question is: To what extent do the three alternatives differ in terms of their effect on controller stress? A randomized block design is used to test the hypothesis of no difference in stress levels for the three workstation alternatives. The data for the experiment is located in the Microsoft Excel Online file below. Use ? = 0.05 to test for any significant differences.arrow_forward
- An investigator reviewed the medical records of 200 children seen for care at Boston Medical Center in the past year who were between the ages 8 and 12 and identified 40 children with asthma. He also identified 40 children of the same ages who were free of asthma. Each child and their family were interviewed to assess whether there might be an association between certain environmental factors such as exposure to second-hand smoke. This study is an example of a: Case-Control Study Crossover Trial Cohort Study Randomized Control Trialarrow_forwardA 2017 article in The New England Journal of Medicine details the results of a randomized clinical trial designed to evaluate the efficacy of a rotavirus gastroenteritis vaccine designed for infants. As per the authors: “Each year, rotavirus gastroenteritis is responsible for about 37% of deaths from diarrhea among children younger than 5 years of age worldwide, with a disproportionate effect in sub-Saharan Africa. We conducted a randomized, placebo-controlled trial in Niger to evaluate the efficacy of a live, oral bovine rotavirus pentavalent vaccine (BRV-PV, Serum Institute of India) to prevent severe rotavirus gastroenteritis. Healthy infants received three doses of the vaccine or placebo at 6, 10, and 14 weeks of age. Episodes of rotavirus gastroenteritis were assessed through active and passive surveillance.” The following Kaplan-Meier curves show the time to a diagnosis of rotavirus gastroenteritis separately for the vaccine and placebo samples. Infants were followed for up to 60…arrow_forwardIn a randomized double-blind clinical trials of a new vaccine children were randomly divided into two groups subjects in group one received the new vaccine while subjects in group 2 received a control vaccine after the second dose 112 of 690 subjects in the experimental group 1 experienced drowsiness as a side effect after the second dose 69 of 571 of the subjects in the control group 2 experienced drowsiness as a side effect does the evidence suggest that a higher proportion of subjects in group 1 experience drowsiness as a side effect than subjects in group 2 at 0.05 level of significance? Determine the null and alternative hypothesis? find the test statistic for this hypothesis test? determine the P value for this hypothesis test? do we reject or not reject the null hypothesis and why? State your conclusion?arrow_forward
- MATLAB: An Introduction with ApplicationsStatisticsISBN:9781119256830Author:Amos GilatPublisher:John Wiley & Sons IncProbability and Statistics for Engineering and th...StatisticsISBN:9781305251809Author:Jay L. DevorePublisher:Cengage LearningStatistics for The Behavioral Sciences (MindTap C...StatisticsISBN:9781305504912Author:Frederick J Gravetter, Larry B. WallnauPublisher:Cengage Learning
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