Concept explainers
It is commonplace to gain weight after quitting smoking. To determine the effectiveness of the drug Naltrexone in limiting weight gain after quitting smoking, 147 subjects who smoked 20 or more cigarettes daily were randomly divided into two groups. All 147 subjects received a 21-milligram (mg) transdermal nicotine patch (to curb nicotine cravings while trying to quit smoking). However, seventy-two subjects received a placebo, while 75 received 25 mg of Naltrexone. After 6 weeks, the placebo subjects had a
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Fundamentals of Statistics (5th Edition)
- In a study conducted by the U.S. Department of Health and Human Services, a sample of 546 boys aged 6–11 was weighed, and it was determined that 87 of them were overweight. A sample of 508 girls aged 6–11 was also weighed, and 74 of them were overweight. Can you conclude that the proportion of boys who are overweight differs from the proportion of girls who are overweight?arrow_forwardA recent study on the effects of Tamiflu looked into whether the antiviral medication can reduce the duration of the flu or not. To test this, researchers selected sample of 42 individuals recently diagnosed with the flu. Twenty-one of these individuals were given a placebo, and their average flu durations was 12.6 days (SD = 1.88). The remaining 21 subjects were given Tamiflu, and their average flu duration was 11.4 days (SD = 1.58). Did Tamiflu make reduce the duration of the flu? What is the effect size for this difference? state the null and alternavive hypthesis, aplha level of 0.05 please text the null hypthesis and draw the rejction regionarrow_forwardIn a clinical trial of 2198 subjects treated with a certain drug, 26 reported headaches. In a control group of 1661 subjects given a placebo, 22 reported headaches. Denoting the proportion of headaches in the treatment group by p, and denoting the proportion of headaches in the control (placebo) group by Pc the relative risk is p/pc. The relative risk is a measure of the strength of the effect of the drug treatment. Another such measure is the odds ratio, which is the ratio of the odds in favor of a headache for the treatment group to the odds in favor of a headache for the control (placebo) group, found by evaluating . The relative risk and odds ratios are commonly used in medicine and epidemiological studies. Find the relative risk and odds ratio for the headache data. What do the results suggest about the risk of a headache from the drug treatment? Pt/(1-Pt) Pc/(1-Pc)arrow_forward
- An article describes a study in which a new type of ointment was applied to forearms of volunteers to study the rates of absorption into the skin. Eight locations on the forearm were designated for ointment application. The new ointment was applied to six locations, and a control was applied to the other two. How many different choices were there for the six locations to apply the new ointment?arrow_forwardA group of disabled women ages 65 and older were followed for several years. It was found that those who had a vitamin B12 deficiency were twice as likely to suffer from severe depressions than those who did not.a. Describe the type of study being performed.b. Describe the explanatory variable(s) and response variable(s).arrow_forwardDr. Guidry conducts a study examining the relationship between the number of friends one has and the experience of daily stress and life satisfaction. She randomly samples 1,500 elderly men and women in Nashville, Tennessee (the state capital), located in the southern United States. Below are her findings.• Life satisfaction and experience of daily stress: r = .57 (p = .01)• Number of friends one has and experience of daily stress: r = .09, not sig.• Number of friends one has and life satisfaction: r = .36 (p = .04) Which of the following conclusions can Dr. Guidry draw about the number of friends one has and life satisfaction based on her statistical analyses? a. The probability of her sample coming from a zero association population is about 4%. (correct answer) b. The probability of her sample coming from a zero association population is about 96%. c. The relationship is not statistically significant. d. The strong correlation means that the number of friends one has causes an…arrow_forward
- Dr. Guidry conducts a study examining the relationship between the number of friends one has and the experience of daily stress and life satisfaction. She randomly samples 1,500 elderly men and women in Nashville, Tennessee (the state capital), located in the southern United States. Below are her findings.• Life satisfaction and experience of daily stress: r = .57 (p = .01)• Number of friends one has and experience of daily stress: r = .09, not sig.• Number of friends one has and life satisfaction: r = .36 (p = .04) In determining whether the relationship between two of Dr. Guidry’s variables was statistically significant, which of the following must be considered? a. Sample size and number of variables analyzed b. Direction of the association and strength of the association c. Sample size and effect size d. The number of outliers and the direction of the association Answer is C. But why? Why,b,c,d are wrong?arrow_forwardA headache medicine is tested on an experimental group of 50 patients who have headaches. Out of these people, 37 of them say they felt better when taking the medicine. A fake pill (placebo) is given to 50 different patients, of whom 27 say they felt better after taking the "medicine". Is this enough evidence to show that a higher percentage of people in the experimental group were cured, compared to the control group? (Use a = .01) Type of Test: Hypotheses: Test Statistic: P-value: Decision: XC. In a sentence, what can be said about the medicine?arrow_forwardOver the past few decades, public health officials have examined the link between weight concerns and teen girls' smoking. Researchers surveyed a group of 273 randomly selected teen girls living in Massachusetts (between 12 and 15 years old). After four years the girls were surveyed again. Sixty-three said they smoked to stay thin. Is there good evidence that more than thirty percent of the teen girls smoke to stay thin?After conducting the test, what are your decision and conclusion? Reject H0: There is sufficient evidence to conclude that less than 30% of teen girls smoke to stay thin. Do not reject H0: There is not sufficient evidence to conclude that less than 30% of teen girls smoke to stay thin. Reject H0: There is not sufficient evidence to conclude that more than 30% of teen girls smoke to stay thin. Reject H0: There is sufficient evidence to conclude that more than 30% of teen girls smoke to stay thin. Do not reject H0: There is not sufficient evidence to conclude that…arrow_forward
- A random sample of 20 young men was taken. One half of the group was given coffee containing caffeine while the other half was given decaffeinated coffee as the placebo control. The pulse rate was measured after the subjects have drunk their coffee. The results were: n x2sPlacebo 12 65 31.11 Caffeine 8 78 28.67arrow_forwardIn this study, ten combat veterans undergoing treatment for PTSD were randomly sampled from a local VA hospital in a study designed to test the efficacy of an anti-anxiety medication in reducing the symptoms of PTSD. Based on clinical animal trials, the researchers predict that the drug should reduce symptoms. t= 1.63, df=9, p=0.064, d= 0.529. Before: M= 48.100, SD=1.370, SE=0.433 After: M= 47.000, SD= 1.491, SE= 0.471 My hypotheses are; H0: μbefore ≤ μafter. H1: μbefore > μafter A. State your findings in APA format: B. How would you explain these findings to someone who has never taken a statistics class? In other words, use clear direct, non-jargon language to explain the results:arrow_forwardEllen Davis Jones studied the effects of reminiscence therapy for older women with depression. She studied 15 women 60 years or older residing for 3 months or longer in an assisted living long-term care facility. For this study, depression was measured by the Geriatric Depression Scale (GDS). Higher scores indicate more severe depression symptoms. The participants received reminiscence therapy for long-term care, which uses family photographs, scrapbooks, and personal memorabilia to stimulate memory and conversation among group members. Pre-treatment and post-treatment depression scores are given in the following table. Can we conclude, based on these data, that subjects who participate in reminiscence therapy exercise, on average, a decline in GDS depression scores? Assume that alpha = 0.01. Pre-GDS 12 10 16 2 12 18 11 16 10 14 Post-GDS 11 10 11 3 9 13 8 14 10 12 What is the null and alternative hypothesis…arrow_forward
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