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Reliance on solid biomass fuel for cooking and heating exposes many children from developing countries to high levels of indoor air pollution. The article “Domestic Fuels, Indoor Air Pollution, and Children’s Health” (Annals of the N.Y. Academy of Sciences, 2008: 209–217) presented information on various pulmonary characteristics in samples of children whose households in India used either biomass fuel or liquefied petroleum gas (LPG). For the 755 children in biomass households, the sample
For the 750 children whose households used liquefied petroleum gas, the sample mean PEF was 4.25 and the sample standard deviation was 1.75.
a. Calculate a confidence interval at the 95% confidence level for the population mean PEF for children in biomass households and then do likewise for children in LPG households. What is the simultaneous confidence level for the two intervals?
b. Carry out a test of hypotheses at significance level .01 to decide whether true average PEF is lower for children in biomass households than it is for children in LPG households (the cited article included a P-value for this test).
c. FEV1, the forced expiratory volume in 1 second, is another measure of pulmonary
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Chapter 9 Solutions
Probability and Statistics for Engineering and the Sciences
- The authors of the paper "Statistical Methods for Assessing Agreement Between Two Methods of Clinical Measurement"† compared two different instruments for measuring a person's ability to breathe out air. (This measurement is helpful in diagnosing various lung disorders.) The two instruments considered were a Wright peak flow meter and a mini-Wright peak flow meter. Seventeen people participated in the study, and for each person air flow was measured once using the Wright meter and once using the mini-Wright meter. Subject Mini-WrightMeter WrightMeter Subject Mini-WrightMeter WrightMeter 1 512 494 10 445 433 2 430 395 11 432 417 3 520 516 12 626 656 4 428 434 13 260 267 5 500 476 14 477 478 6 600 557 15 259 178 7 364 413 16 350 423 8 380 442 17 451 427 9 658 650 (a) Suppose that the Wright meter is considered to provide a better measure of air flow, but the mini-Wright meter is easier to transport and to use. If the two types of meters produce…arrow_forwardThe authors of the paper "Statistical Methods for Assessing Agreement Between Two Methods of Clinical Measurement" compared two different instruments for measuring a subject's ability to breathe out air.† (This measurement is helpful in diagnosing various lung disorders.) The two instruments considered were a Wright peak flow meter and a mini-Wright peak flow meter. Seventeen subjects participated in the study, and for each subject air flow was measured once using the Wright meter and once using the mini-Wright meter. Subject 1 2 3 4 5 6 7 8 9 Mini- Wright Meter 512 430 520 428 500 600 364 380 658 Wright Meter + 494 395 516 434 476 557 413 442 650 Subject 10 11 12 13 14 15 16 17 Mini- Wright Meter 445 432 626 260 477 259 350 451 Wright Meter 433 417 656 267 478 178 423 427 (a) Suppose that the Wright meter is considered to provide a better measure of air flow, but the mini-Wright meter is easier to transport and to use. If the two types of meters produce different readings but there is…arrow_forwardThe authors of the paper "Statistical Methods for Assessing Agreement Between Two Methods of Clinical Measurement" compared two different instruments for measuring a subject's ability to breathe out air.+ (This measurement is helpful in diagnosing various lung disorders.) The two instruments considered were a Wright peak flow meter and a mini-Wright peak flow meter. Seventeen subjects participated in the study, and for each subject air flow was measured once using the Wright meter and once using the mini-Wright meter. Mini- Subject Wright Meter 1 2 3 4 5 6 7 8 9 512 430 520 428 500 600 364 380 658 Wright Meter 494 395 516 434 476 557 413 442 650 Subject 10 11 12 13 14 15 16 17 Mini- Wright Meter 445 432 626 260 477 259 350 451 Wright Meter 433 417 656 267 478 178 423 427 (a) Suppose that the Wright meter is considered to provide a better measure of air flow, but the mini-Wright meter is easier to transport and to use. If the two types of meters produce different readings but there is a…arrow_forward
- The authors of the paper "Statistical Methods for Assessing Agreement Between Two Methods of Clinical Measurement" compared two different instruments for measuring a subject's ability to breathe out air.† (This measurement is helpful in diagnosing various lung disorders.) The two instruments considered were a Wright peak flow meter and a mini-Wright peak flow meter. Seventeen subjects participated in the study, and for each subject air flow was measured once using the Wright meter and once using the mini-Wright meter. Subject Mini-WrightMeter WrightMeter Subject Mini-WrightMeter WrightMeter 1 512 494 10 445 433 2 430 395 11 432 417 3 520 516 12 626 656 4 428 434 13 260 267 5 500 476 14 477 478 6 600 557 15 259 178 7 364 413 16 350 423 8 380 442 17 451 427 9 658 650 (a) Suppose that the Wright meter is considered to provide a better measure of air flow, but the mini-Wright meter is easier to transport and to use. If the two types of meters produce…arrow_forwardThe background concentration of a chemical in soil was measured on ten random specimens of soil from an uncontaminated area. The measured concentrations, in mg/kg, are: 1.4, 0.6, 1.2, 1.6, 0.5, 0.7, 0.3, 0.8, 0.2, and 0.9. Soil from a neighboring area will be declared “contaminated” if test specimens contain a chemical concentration higher than the upper 99% confidence limit of the background level. What is the cleanup target concentration?arrow_forwardCadmium, a heavy metal, is toxic to animals. Mushrooms, however, are able to absorb and accumulate cadmium at high concentrations. The Czech and Slovak governments have set a safety limit for cadmium in dry vegetables at 0.5 part per million (ppm). M. Melgar et al. measured the cadmium levels in a random sample of the edible mushroom Boletus pinicola and published the results in the paper “Influence of Some Factors in Toxicity and Accumulation of Cd from Edible Wild Macrofungi in NW Spain” (Journal of Environmental Science and Health, Vol. B33(4), pp. 439–455). A hypothesis test is to be performed to decide whether the mean cadmium level in Boletus pinicola mushrooms is greater than the government’s recommended limit. Hypothesis tests are proposed. For each hypothesis test,a. determine the null hypothesis.b. determine the alternative hypothesis.c. classify the hypothesis test as two tailed, left tailed, or right tailed.arrow_forward
- Could it be that smoking actually increases survival rates among women? The accompanying data represent the 20-year survival status and smoking status of 1339 women who participated in a 20-year cohort study. Complete parts (a) through (e).arrow_forwardBenzene is a pollutant that, according to studies, can be associated with health problems. Benzene is found in air, water, and soil and comes from both industrial and natural sources. Benzene levels in indoor air are generally higher than outdoors. The main source of benzene in indoor air appears to be tobacco smoke, thus the combustion of tobacco is a major source of pollution. Benzene levels are measured in a random sample of 36 bars in a city, obtaining an average benzene level of 19.2 mg / m3, with a standard deviation of 2.1 mg / m3. Estimate the mean benzene level in bars in this city using a 95% confidence interval. (do your calculations to 4 decimal places) (need the process can be by hand ,Excel or R.) a)Other solution b)[18.48946, 19.91054] c)[19.0950, 19.3050] d)[18.5140, 19.8859] e)[18.6243, 19.7757] f)[18.4315, 19.7936]arrow_forwardThe death rate per 100,000 for lung cancer is 7 among non-smokers and 71 among smokers. The death rate per 100,000 for coronary thrombosis is 422 among non-smokers and 599 among smokers. The prevalence of smoking in the population is 55%. The relative risk of dying for a smoker compared to a non-smoker is: [Refer to the chapter titled “Study Designs: Cohort Studies”] A. 9.1 for lung cancer and 0.30 for coronary thrombosis. B. 10.1 for lung cancer and 1.4 for coronary thrombosis. C. 10.1 for lung cancer and 8.4 for coronary thrombosis. D. 9.1 for lung cancer and 1.4 for coronary thrombosis. E. 12.4 for lung cancer and 1.7 for coronary thrombosis.arrow_forward
- The article “Arsenic and Mercury in Lake Whitefish and Burbot Near the Abandoned Giant Mine on Great Slave Lake” (P. Cott, B. Zajdlik, et al., Journal of Great Lakes Research, 2016:223–232) presents measurements of arsenic concentrations in fish found in Northern Canada. In a sample of 8 whitefish caught in Yellowknife Bay, the mean arsenic concentration in the liver was 0.32 mg/kg, with a standard deviation of 0.05 mg/kg. Can you conclude that the mean arsenic concentration in whitefish in Yellowknife Bay is greater than 0.3 mg/kg?arrow_forwardA study was made of 1,057 cases of poisoning in children treated as inpatients at Milwaukee Children's Hospital from 1962 through 1968. Data on date of occurrence, age and sex of the child, and type of agent involved were recorded and analyzed by standard statistical methods. Poisoning was due to ingestion of aspirin in 35 per cent of the children studied and to the ingestion of hydrocarbon distillates in 18 per cent. A statistically significant male dominance was found for ingestion of hydrocarbons; age-specific peaks were found for some categories. Trends as to the relative and absolute frequencies of each specific poison from one year to the next were noted; possible reasons for increasing or decreasing trends are discussed. Is this study descriptive or inferential? Explain your answer. What are the variables used in the study? In your opinion, what level of measurement was used to obtain the data from the variables? Does the article define the population? If so, how is it…arrow_forwardAnemia (low healthy blood cells or hemoglobin) has an important role in exercise performance. However, the direct link between rapid changes of hemoglobin and exercise performance is still unknown. A study investigated 18 patients with a blood disorder (beta-thalassemia). Participants in the study performed an exercise test before and the day after receiving a blood transfusion. Data are given in the table. HB = Hemoglobin RER = Respiratory exchange ID Change in HB Obese RER > 1.1 ratio No No 1 -1.4 No -1.5 No Yes No Yes 3 -2 No 4 -2.1 No -1.9 Yes Yes No -1.6 -1.8 -0.8 6 7 No Yes No Yes 8 9. -1 No No -1.2 No Yes 10 11 No No -0.8 -1.5 12 Yes No No Yes 13 14 -1.4 -2.6 -1.7 No No Yes Yes 15 Yes No Yes Yes 16 -2.6 No 17 18 -2.7 -1.5 Noarrow_forward
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