In Exercises 5–16, test the given claim.
8. Second-Hand Smoke Data Set 12 “Passive and Active Smoke” includes cotinine levels measured in a group of smokers (n = 40,
a. Use a 0.05 significance level to test the claim that the variation of cotinine in smokers is greater than the variation of cotinine in nonsmokers not exposed to tobacco smoke.
b. The 40 cotinine measurements from the nonsmoking group consist of these values (all in ng/mL): 1, 1, 90, 244, 309, and 35 other values that are all 0. Does this sample appear to be from a
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Chapter 9 Solutions
ELEMENTARY STATISTICS WITH MYSTATLAB
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- t=? critical value=? reject/enough evidence/not enough evidence/fail=?arrow_forwardA paper investigated the driving behavior of teenagers by observing their vehicles as they left a high school parking lot and then again at a site approximately 1 2 mile from the school. Assume that it is reasonable to regard the teen drivers in this study as representative of the population of teen drivers. Amount by Which Speed Limit Was Exceeded MaleDriver FemaleDriver 1.2 -0.1 1.4 0.4 0.9 1.1 2.1 0.7 0.7 1.1 1.3 1.2 3 0.1 1.3 0.9 0.6 0.5 2.1 0.5 (a) Use a .01 level of significance for any hypothesis tests. Data consistent with summary quantities appearing in the paper are given in the table. The measurements represent the difference between the observed vehicle speed and the posted speed limit (in miles per hour) for a sample of male teenage drivers and a sample of female teenage drivers. (Use μmales − μfemales.Round your test statistic to two decimal places. Round your degrees of freedom down to the nearest whole number. Round your p-value to…arrow_forwardEvans conducted a study to determine if the frequency and characteristics of pediatric problems in elderly patients with diabetes present differences with respect to patients of the same age, but without diabetes. The individuals studied, interned in a clinic, were between 70 and 90 years old. Among the researchers' findings are the following statistics. with respect to the scores on the deep tendon reflexes meters:Sample without Diabetes: 79 / 2.1 / 1.1With Diabetes: 74 / 1.6 / 1.2Is it possible to conclude, based on the data, that, on average, diabetic patients they have reduced deep tendon reflexes in comparison with patients without diabetes of the same age?arrow_forward
- research team wants to investigate the impact of increased sun exposure to a decrease in depression. In order to do so, the team gathers a SRS of 124 individuals with a sample average score on the Geriatric Depression Scale (GDS) of 7.5 from a population with σ=.4 after consistent sun exposure above 7 hours a day. Assume a clinical diagnosis for depression can only be given with a GDS score of 9. A) Is the team correct in their hypothesis? B) State and interpret your results.arrow_forwardThe performance of two analysts in determining total mercury (mg / kg) in fish was evaluated using the absorption spectrometry method. The results on the concentrations of mercury found in fish, for each analyst, are presented in the table below: Analyst 1 Analyst 2 7 12 9 8 6 9 11 13 13 14 8 9 7 8 13 10 12 7 9 15 (a)Is the performance in determining total mercury for Analyst 1 more accurate than Analyst 2? Compare the accuracy in the results of the two analysts at a 95% confidence level. Explain. (b)Are the results obtained by the two analysts, in the concentrations of mercury found in the fish, statistically equivalent, with 95% confidence? Explainarrow_forwardA dietitian wishes to see if a person’s cholesterol level will be changed if the diet is supplemented by a certain mineral. Four subjects were pre-tested, and they took the mineral supplement for a 6-week period. The results are shown in the table. Is there sufficient evidence to conclude that the population mean of cholesterol levels has been changed after six weeks at α=0.2α=0.2? Assume that the differences are from an approximately normally distributed population. Subject Cholestrol Level (mg/dl) Cholestrol Level after 6 Weeks (mg/dl) dd ¯dd¯ (d−¯d)2(d-d¯)2 1 206 217 11 2 219 184 -35 3 202 204 2 4 213 205 -8 Total -30 a) Calculate the mean, the sum of the squared deviation from the mean, and the standard deviation of differences. Do not include the unit for each answer: ¯d=d¯= (do not round) ∑(d−¯d)2=∑(d-d¯)2= (do not round) sd=sd= (rounded to one decimal place) b) Perform the hypothesis test in the following steps: Step 1.…arrow_forward
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