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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)
- A psychologist has developed a mental alertness test. She wishes to study the effects (if any) of type of food consumed on mental alertness. Twenty-one volunteers were randomly divided into two groups. Both groups were told to eat the amount they usually eat for lunch at noon. At 2:00 P.M., all subjects were given the alertness test. Group A had a low-fat lunch with no red meat, lots of vegetables, carbohydrates, and fiber. Group B had a high-fat lunch with red meat, vegetable oils, and low fiber. The only drink for both groups was water. The test scores are shown below. Group A 67 93 82 69 76 47 43 58 92 63 52 Group B 70 57 75 59 66 49 55 46 45 91 89 72 Use a 10% level of significance to test the claim that there is no difference in mental alertness distributions based on type of lunch. (a) What is the level of significance? (b) Compute the sample test statistic. (Use 2 decimal places.) (c) Find the P-value of the sample test statistic. (Use 4 decimal places.)arrow_forwardA psychologist has developed a mental alertness test. She wishes to study the effects (if any) of type of food consumed on mental alertness. Twenty-one volunteers were randomly divided into two groups. Both groups were told to eat the amount they usually eat for lunch at noon. At 2:00 P.M., all subjects were given the alertness test. Group A had a low-fat lunch with no red meat, lots of vegetables, carbohydrates, and fiber. Group B had a high-fat lunch with red meat, vegetable oils, and low fiber. The only drink for both groups was water. The test scores are shown below. Group A 75 82 96 54 78 59 67 53 97 85 66 Group B 70 80 79 60 62 71 52 69 64 88 51 74 Use a 10% level of significance to test the claim that there is no difference in mental alertness distributions based on type of lunch. (a) What is the level of significance?State the null and alternate hypotheses. Ho: Distributions are different. H1: Distributions are the same.Ho: Distributions are the same. H1:…arrow_forwardOver a 4-month period, among 30 people with bipolar disorder, patients who were given a high dose (10 g/day) of omega-3 fats from fish oil improved more than those given a placebo. This experiment involved a control group of subjects who received a placebo. Why didn't the experimenters just give everyone the omega-3 fats to see if they improved? Choose the correct answer below. O A. They need to avoid confounding the participants. O B. They need to compare omega-3 results to something. O C. They need to conserve omega-3 fats. O D. They need to blind the participants.arrow_forward
- Researchers wanted to know the effectiveness of a new anti-venom shot. A study was conducted on 245 children who had nonlethal scorpion stings. The ages of the children ranged from 6 months to 18 years old. Each child was randomly assigned to receive a shot of the anti-venom or a placebo shot. Researchers recorded whether or not their condition improved over the next four hours. They found that about 73% of the children who were given anti-venom saw an improvement in their condition whereas only about 23% of the children who were given the placebo saw an improvement in their condition. Identify the population.The population is all children 6 months to 18 years old with nonlethal scorpion stings. Identify the sample.The sample is 245 children 6 months to 18 years old with nonlethal scorpion stings. What is the treatment variable? The treatment variable is the anti-venom shot. What is the response (or outcome) variable?The outcome variable is improvements in their condition.…arrow_forwardA marketing researcher measures 100 doctors’ reports of the number of their patients asking them about a particular drug during the month before and after a major advertising campaign What kind of t-test should be used?arrow_forwardA county environmental agency suspects that the fish in a particular polluted lake have elevated mercury levels. To confirm that suspicion, five striped basses in that lake were caught and their tissues were tested for mercury. For the purpose of comparison, four striped basses in an unpolluted lake were also caught and tested. The fish tissue mercury levels in mg/kg are given below. Sample I(From Polluted Lake) 0.523 0.723 0.523 0.623 0.523 Sample II(From Unpolluted Lake) 0.323 0.223 0.523 0.323 0.000 (a) Construct the 95% confidence interval for the difference in the population means based on these data. (b) Test, at the 5% level of significance, whether the data provide sufficient evidence to conclude that fish in the polluted lake have elevated levels of mercury in their tissue.arrow_forward
- Determine whether the study depicts an observational study or an experimental study. A study was done to see if sugar consumption can cause hypoeractivity in children. The researcher took four groups of children and assigned different amounts of sugar the children had to consume. After a certain period of time, they assessed whether or not the children were hyperactive.arrow_forwardAt OC, students have been surveyed to see whether they attend orientation. The data is as follows: Woman Men Yes 162 112 No 148 125 Is there enough evidence to show that a higher percentage of woman attend orientation? Use ( .01 as alpha)arrow_forwardResearchers studied 208 infants whose brains were temporarily deprived of oxygen due to complications at birth. When researchers detected oxygen deprivation, they randomly assigned babies to either usual care or to a whole-body cooling group. The goal was to see whether reducing body temperature for three days after birth increased the rate of survival without brain damage. What is the explanatory variable? A. Survival without brain damage B.Infants whose brains are temporarily deprived of oxygen C. Usual care or whole-body coolingarrow_forward
- In a study conducted in Italy, 10 patients with hypertriglyceridemia were placed on a low-fat, high-carbohydrate diet. Before the start of the diet, cholesterol and triglyceride measurements were recorded for each subject. Patient Cholesterol Level (mmol/l) Triglyceride level (mmol/l) 1 5.12 2.30 2 6.18 2.54 3 6.77 2.95 4 6.65 3.77 5 6.36 4.18 6 5.90 5.31 7 5.48 5.53 8 6.02 8.83 9 10.34 9.48 10 8.51 14.20 a. Construct a two-way scatter plot for these data. b. Use STATA to calculate Pearson’s Correlation Coefficient for these data. c. Test, α = 0.05, whether or not the population correlation, ρ, equals 0.arrow_forwardIn a study conducted in Italy, 10 patients with hypertriglyceridemia were placed on a low-fat, high-carbohydrate diet. Before the start of the diet, cholesterol and triglyceride measurements were recorded for each subject. Patient Cholesterol Level (mmol/l) Triglyceride level (mmol/l) 1 5.12 2.30 2 6.18 2.54 3 6.77 2.95 4 6.65 3.77 5 6.36 4.18 6 5.90 5.31 7 5.48 5.53 8 6.02 8.83 9 10.34 9.48 10 8.51 14.20A. Use STATA to Calculate the Spearman rank correlation coefficient, rs, for these data. B. Using rs, test the null hypothesis that the population correlation, ρ, equals 0.arrow_forwardA group of 500 children who suffer from asthma were asked to participate in a study to determine the effectiveness of a new medication. The patients were randomly divided into two groups: one that was given the actual medication and one that received a placebo. The results of the study are below. What percentage of patients who took the medication had improved symptoms? Symptoms improved Symptoms did not improve Medication Placebo 205 65 140 90 O 65.2% O 75.9% O 41% O 54%arrow_forward
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