The negative effects of ambient air pollution on children’s lung
- a. Calculate and interpret a 95% (two-sided) confidence interval for true average FEV1 level in the population of all children from which the sample was selected. Does it appear that the parameter of interest has been accurately estimated?
- b. Suppose the investigators had made a rough guess of 320 for the value of s before collecting data. What
sample size would be necessary to obtain an interval width of 50 ml for a confidence level of 95%?
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Chapter 7 Solutions
Student Solutions Manual for Devore's Probability and Statistics for Engineering and the Sciences, 9th
- Reduced heart rate variability (HRV) is known to be a predictor of mortality after a heart attack. One measure of HRV is the average normal-to-normal beat interval (in milliseconds) for a 24-hr time period. Twenty-two heart attack patients who were dog owners and 80 heart attack patients who did not own a dog participated in a study of the effect of pet ownership on HRV, resulting in the summary statistics shown in the accompanying table. Measure of HRV(Average Normal-to-Normal Beat Interval) Mean StandardDeviation Owns Dog 871 134 Does Not Own Dog 800 138 (b) The paper indicates that the null hypothesis in part (a) was rejected and reported that the P-value was less than 0.05. Carry out a two-sample t test. (Use ? = 0.05. Use ?1 for heart attack patients who are dog owners and ?2 for heart attack patients who do not own a dog.) Find the test statistic and P-value. (Use SALT. Round your test statistic to one decimal place and your P-value to three decimal places.) t=…arrow_forwardReduced heart rate variability (HRV) is known to be a predictor of mortality after a heart attack. One measure of HRV is the average normal-to-normal beat interval (in milliseconds) for a 24-hr time period. Twenty-two heart attack patients who were dog owners and 80 heart attack patients who did not own a dog participated in a study of the effect of pet ownership on HRV, resulting in the summary statistics shown in the accompanying table. The authors of this paper used a two-sample t test to test H0: ?1 − ?2 = 0 versus Ha: ?1 − ?2 ≠ 0. What conditions must be met in order for this to be an appropriate method of analysis? (Select all that apply.) Find the test statistic and P-value.arrow_forwardHeight and Breast Cancer. In the article “Height and Weight at Various Ages and Risk of Breast Cancer” (Annals of Epidemiology, Vol. 2, pp. 597–609), L. Brinton and C. Swanson discussed the relationship between height and breast cancer. The study, sponsored by the National Cancer Institute, took 5 years and involved more than 1500 women with breast cancer and 2000 women without breast cancer; it revealed a trend between height and breast cancer: “. . . taller women have a 50 to 80 percent greater risk of getting breast cancer than women who are closer to 5 feet tall.” Christine Swanson, a nutritionist who was involved with the study, added, “. . . height may be associated with the culprit, . . . but no one really knows” the exact relationship between height and the risk of breast cancer. a. Classify this study as either an observational study or a designed experiment. Explain your answer. b. Interpret the statement made by Christine Swanson in light of your answer to part (a).arrow_forward
- 2. Does the herb Echinacea help the common cold? A study investigated the impact of echinacea vs. a standard cold medication on cold symptoms. Each subject in the study chose to take either the echinacea or a standard cold medication in capsule fom After taking the capsule for one week, the subjects then reported to the researchers the status of their cold symptoms. The researchers subsequently reported that there was no statistically significant difference in the duration of the cold between these groups. Identify the type of study. a) Cluster sample b) Social acceptability bias c) Experiment d) Observational studyarrow_forwardReduced heart rate variability (HRV) is known to be a predictor of mortality after a heart attack. One measure of HRV is the average normal-to-normal beat interval (in milliseconds) for a 24-hr time period. Twenty-two heart attack patients who were dog owners and 80 heart attack patients who did not own a dog participated in a study of the effect of pet ownership on HRV, resulting in the summary statistics shown in the accompanying table.arrow_forwardA study is being conducted on the effect of gas price on the number of miles driven in a given month. Residents in two cities, one on the East Coast and one on the West Coast, are randomly selected and asked to complete a questionnaire on the type of car they drive, the number of miles they live from work, the number of children under 18 in their household, their monthly income, and the number of miles they have driven over the past 30 days. State whether this study is an experimental or observational study? Explain in brief the reason for your answer.arrow_forward
- Reduced heart rate variability (HRV) is known to be a predictor of mortality after a heart attack. One measure of HRV is the average of normal-to-normal beat interval (in milliseconds) for a 24-hour time period. Twenty-two heart attack patients who were dog owners and 80 heart attack patients who did not own a dog participated in a study of the effect of pet ownership on HRV, resulting in the summary statistics shown in the accompanying table. Measure ofHRV (averagenormal-to-normalbeat interval) Mean StandardDeviation Owns Dog 874 136 Does Not Own Dog 801 133 (a) The authors of this paper used a two-sample t test to test H0: ?1 - ?2 = 0 versus Ha: ?1 - ?2 ≠ 0. What assumptions must be reasonable in order for this to be an appropriate method of analysis?We must assume that the population distributions ---Select--- are aren't approximately normal.(b) The paper indicates that the null hypothesis from Part (a) was rejected and reports that the P-value is less than…arrow_forward2. The city council is considering a law that would ban concealed weapons in all public facilities. A sample has been selected from the community and surveyed about support for the proposed ordinance. Is there a statistically significant relationship between age and support for the law against carrying concealed weapons (use p=.05, χ2(critical) = 3.841)? Use the five step model as a guide and write a sentence or two interpreting your results. Age Under 40 40 and older Support For 142 77 219 Against 106 170 276 248 247 495arrow_forwardElissa Epel, a professor of health psychology at the University of California–San Francisco, studied women in high- and low-stress situations. She found that women with higher cortisol responses to stress ate significantly more sweet food and consumed more calories on the stress day compared with those with low cortisol responses, and compared with themselves on lower stress days. Increases in negative mood in response to the stressors were also significantly related to greater food consumption. These results suggest that psychophysiological responses to stress may influence subsequent eating behavior. Over time, these alterations could impact both weight and health. You are interested in studying whether students living in the dorms or students living off campus have higher cortisol levels. You ask a sample of n₁ = 25 students living in the dorms and n₂ = 30 students living off campus to record their afternoon cortisol levels for a week. The average cortisol level for students living…arrow_forward
- Researchers have sought to examine the effect of various types of music on agitation levels in patients who are in the early and middle stages of Alzheimer's disease. Patients were selected to participate in the study based on their stage of Alzheimer's disease. Three forms of music were tested: Easy listening, Mozart, and piano interludes. While listening to music, agitation levels were recorded for the patients with a high score indicating a higher level of agitation. Scores are recorded below. Group Piano Interlude Mozart Easy Listening Early Stage Alzheimer's 2124221820 Mean=21.0 9121059 Mean=9.0 2926302426 Mean=27.0 Middle Stage Alzheimer's 2220251820 Mean=21.0 141811913 Mean=13.0 1518201319 Mean=17.0 Complete the following ANOVA table. Source df SS MS F Type of Music 2 740 Degree of Alzheimer's 1 30 Interaction 2 260 Error 24 178 Total 29 1208…arrow_forwardThe 5-year incidence of cardiovascular disease (CVD) in relation to smoking status was determined in a population sample of 1000 men, 18 years and older. At baseline, 30% of the men were classified as being current smokers and 70% as being non-smokers. At the end of the follow-up, 60 CVD events had occurred among the smokers and 70 events among the non-smokers. Construct a 2 x 2 table based on the data providedarrow_forwardElissa Epel, a professor of health psychology at the University of California-San Francisco, studied women in high- and low-stress situations. She found that women with higher cortisol responses to stress ate significantly more sweet food and consumed more calories on the stress day compared with those with low cortisol responses, and compared with themselves on lower stress days. Increases in negative mood in response to the stressors were also significantly related to greater food consumption. These results suggest that psychophysiological responses to stress may influence subsequent eating behavior. Over time, these alterations could impact both weight and health. You are interested in studying whether college juniors or college sophomores consume more calories. You ask a sample of n, = 35 college juniors and n2 = 40 college sophomores to record their daily caloric intake for a week. The average daily caloric intake for college juniors was M1 2,423 calories, with a standard…arrow_forward
- Big Ideas Math A Bridge To Success Algebra 1: Stu...AlgebraISBN:9781680331141Author:HOUGHTON MIFFLIN HARCOURTPublisher:Houghton Mifflin Harcourt