Concept explainers
As the population ages, there is increasing concern about accident-related injuries to the elderly. The article “Age and Gender Differences in Single-Step Recovery from a Forward Fall” (J. of Gerontology, 1999: M44–M50) reported on an experiment in which the maximum lean angle—the farthest a subject is able to lean and still recover in one step—was determined for both a sample of younger females (21–29 years) and a sample of older females (67–81 years). The following observations are consistent with summary data given in the article:
YF: | 29. | 34, | 33. | 27, | 28, 32, 31, 34, 32, 27 |
OF: | 18, | 15, | 23, | 13, | 12 |
Does the data suggest that true average maximum lean angle for older females is more than 10 degrees smaller than it is for younger females? State and test the relevant hypotheses at significance level .10.
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Chapter 9 Solutions
Student Solutions Manual for Devore's Probability and Statistics for Engineering and the Sciences, 9th
- J 2arrow_forwardResearchers have noted a decline in cognitive functioning as people age (Bartus, 1990). However, the results from other research suggest that the antioxidants in foods such as blueberries may reduce and even reverse these age-related declines (Joseph et al., 1999). To examine this phenomenon, suppose that a researcher obtains a sample of n = 16 adults who are between the ages of 65 and 75. The researcher uses a standardized test to measure cognitive performance for each individual. The participants then begin a 2-month program in which they receive daily doses of a blueberry supplement. At the end of the 2-month period, the researcher again measures cognitive performance for each participant. The results show an average increase in performance of Mp = 7.4 with SS = 1215. a. Does this result support the conclusion that the antioxidant supplement has a significant effect on cognitive performance? Use a two-tailed test with a = = .05. (1) Ho: (Select] ( Select ] [ Select ] H: ( Select ] […arrow_forwardResearchers have noted a decline in cognitive functioning as people age (Bartus, 1990). However, the results from other research suggest that the antioxidants in foods such as blueberries may reduce and even reverse these age-related declines (Joseph et al., 1999). To examine this phenomenon, suppose that a researcher obtains a sample of n = 16 adults who are between the ages of 65 and 75. The researcher uses a standardized test to measure cognitive performance for each individual. The participants then begin a 2-month program in which they receive daily doses of a blueberry supplement. At the end of the 2-month period, the researcher again measures cognitive performance for each participant. The results show an average increase in performance of MD = 7.4 with SS = 1215. Does this result support the conclusion that the antioxidant supplement has a significant effect on cognitive performance? Use a two-tailed test with α = .05. Show your computations.arrow_forward
- Hoaglin, Mosteller, and Tukey (1983) presented data on blood levels of beta-endorphin as a function of stress. They took beta-endorphin levels for 19 patients 12 hours before surgery and again 10 minutes before surgery. The data are presented below, in fmol/ml Based on these data, what effect does increased stressed have on endorphin levels. include: the hypotheses tested (H0 and H1), the test-statistic and its df, the p-value of the test, and the conclusion as it relates to the research question. Participant 12 hours before 10 minutes before 1 10 6.5 2 6.5 14.0 3 8.0 13.5 4 12 18 5 5.0 14.5 6 11.5…arrow_forwardTo illustrate the effects of driving under the influence (DUI) of alcohol, a police officer brought a DUI simulator to a local high school. Student reaction time in an emergency was measured with unimpaired vision and also while wearing a pair of special goggles to simulate the effects of alcohol on vision. For a random sample of nine teenagers, the time (in seconds) required to bring the vehicle to a stop from a speed of 60 miles per hour was recorded. Complete parts (a) and (b). Note: A normal probability plot and boxplot of the data indicate that the differences are approximately normally distributed with no outliers. Click the icon to view the data table. (a) Whether the student had unimpaired vision or wore goggles first was randomly selected. Why is this a good idea in designing the experiment? A. This is a good idea in designing the experiment because it controls for any "learning" that may occur in using the simulator. B. This is a good idea in designing the experiment because…arrow_forwardTo illustrate the effects of driving under the influence (DUI) of alcohol, a police officer brought a DUI simulator to a local high school. Student reaction time in an emergency was measured with unimpaired vision and also while wearing a pair of special goggles to simulate the effects of alcohol on vision. For a random sample of nine teenagers, the time (in seconds) required to bring the vehicle to a stop from a speed of 60 miles per hour was recorded. Complete parts (a) and (b). Note: A normal probability plot and boxplot of the data indicate that the differences are approximately normally distributed with no outliers. Click the icon to view the data table. (a) Whether the student had unimpaired vision or wore goggles first was randomly selected. Why is this a good idea in designing the experiment? O A. This is a good idea in designing the experiment because the sample size is not large enough. B. This is a good idea in designing the experiment because it controls for any "learning"…arrow_forward
- To illustrate the effects of driving under the influence (DUI) of alcohol, a police officer brought a DUI simulator to a local high school. Student reaction time in an emergency was measured with unimpaired vision and also while wearing a pair of special goggles to simulate the effects of alcohol on vision. For a random sample of nine teenagers, the time (in seconds) required to bring the vehicle to a stop from a speed of 60 miles per hour was recorded. Complete parts (a) and (b). Note: A normal probability plot and boxplot of the data indicate that the differences are approximately normally distributed with no outliers. (a) Whether the student had unimpaired vision or wore goggles first was randomly selected. Why is this a good idea in designing the experiment? A.This is a good idea in designing the experiment because the sample size is not large enough. B. This is a good idea in designing the experiment because it controls for any "learning" that may occur in…arrow_forwardTo illustrate the effects of driving under the influence (DUI) of alcohol, a police officer brought a DUI simulator to a local high school. Student reaction time in an emergency was measured with unimpaired vision and also while wearing a pair of special goggles to simulate the effects of alcohol on vision. For a random sample of nine teenagers, the time (in seconds) required to bring the vehicle to a stop from a speed of 60 miles per hour was recorded. Complete parts (a) and (b). Note: A normal probability plot and boxplot of the data indicate that the differences are approximately normally distributed with no outliers. Click the icon to view the data table. (a) Whether the student had unimpaired vision or wore goggles first was randomly selected. Why is this a good idea in designing the experiment? A. This is a good idea in designing the experiment because reaction times are different. B. This is a good idea in designing the experiment because the sample size is not large enough. C.…arrow_forwardAssume that both populations are normally distributed. (a) Test whether μ₁ µ₂ at the α = 0.01 level of significance for the given sample data. (b) Construct a 99% confidence interval about μ₁ - H₂. (a) Test whether μ₁ μ₂ at the α = 0.01 level of significance for the given sample data. Determine the null and alternative hypothesis for this test. OA. Holl #U2 H₁ H1 H2 OB. Ho H₁ H₂ H₁:1₁ > H₂ O C. Ho H₁ = μ¹2 H₁ H₁ > H₂ O D. Ho H₁ H2 H₁ H1 H₂ n X S Population 1 Population 2 18 18 19.2 23.4 5.3 4.3arrow_forward
- To illustrate the effects of driving under the influence (DUI) of alcohol, a police officer brought a DUI simulator to a local high school. Student reaction time in an emergency was measured with unimpaired vision and also while wearing a pair of special goggles to simulate the effects of alcohol on vision. For a random sample of nine teenagers, the time (in seconds) required to bring the vehicle to a stop from a speed of 60 miles per hour was recorded. Complete parts (a) and (b). Note: A normal probability plot and boxplot of the data indicate that the differences are approximately normally distributed with no outliers. Click the icon to view the data table. (a) Whether the student had unimpaired vision or wore goggles first was randomly selected. Why is this a good idea in designing the experiment? A. This is a good idea in designing the experiment because reaction times are different. B. This is a good idea in designing the experiment because it controls for any "learning" that may…arrow_forwardA study published by Babcock and Marks (2010) showed that the average full-time U.S. college student studied for μ = 14 hours per week (SD = 4.8 hours per week) in 2005. We want to know if this average has changed in the past 15 years. In other words, we are going to do a study in which we try to determine whether there has been an impact of the passage of time on the amount of time college students spend studying. We selected a sample of n = 64 of today’s college students and find that they spent an average of M = 12.5 hours per week studying. Does this sample indicate a significant change in the number of hours spent studying? Use a two-tailed test (this means non-directional hypothesis) with α = .05.arrow_forwardTable 4 above is displaying odds ratios for each predictor estimated by a multivariablelogistic regression model with all 6 predictors included at the same time. Based onthis model, what is the minimum number of in-hospital deaths they should have intheir dataset? A) 30 B) 50 C) 60 D) 70arrow_forward
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