The Mastic tree (Pistacia lentiscus) is used in reforestation efforts in southeastern Spain. The article “Nutrient Deprivation Improves Field Performance of Woody Seedlings in a Degraded Semi-arid Shrubland” (R. Trubata, J. Cortina, and A. Vilagrosaa, Ecological Engineering, 2011:1164–1173) presents a study that investigated the effect of adding slow-release fertilizer to the usual solution on the growth of trees. Following are the heights, in cm, of 10 trees grown with the usual fertilizer (the control group), and 10 trees grown with the slow-release fertilizer (treatment). These data are consistent with the
Usual 17.3 22.0 19.5 18.7 19.5
18.5 18.6 20.3 20.3 20.3
Slow-release 25.2 23.2 25.2 26.2 25.0
25.5 25.2 24.1 24.8 23.6
Want to see the full answer?
Check out a sample textbook solutionChapter 6 Solutions
Statistics for Engineers and Scientists
Additional Math Textbook Solutions
An Introduction to Mathematical Statistics and Its Applications (6th Edition)
Probability and Statistics for Engineering and the Sciences
Statistics for Business and Economics (13th Edition)
Business Analytics
Intro Stats, Books a la Carte Edition (5th Edition)
Essentials of Statistics, Books a la Carte Edition (5th Edition)
- The article "Efficient Pyruvate Production by a Multi-Vitamin Auxotroph of Torulopsis glabrata: Key Role and Optimization of Vitamin Levels" (Y. Li, J. Chen, et al., Applied Microbiology and Biotechnology, 2001:680-685) investigates the effects of the levels of several vitamins in a cell culture on the yield (in g/L) of pyruvate, a useful organic acid. The data in the following table are presented as two replicates of a 23 design. The factors are A: nicotinic acid, B: thiamine, and C: biotin. (Two statistically insignificant factors have been dropped. In the article, each factor was tested at four levels; we have collapsed these to two.) в Mean Yield Yields 0.55, 0.49 A. -1 -1 -1 0.520 -1 -1 0.60, 0.42 0.37, 0.28 0.30, 0.28 0.54, 0.54 0.54, 0.47 0.44, 0.33 0.36, 0.20 0.510 0.325 0.290 -1 -1 -1 -1 -1 1. 0.540 -1 0.505 -1 0.385 0.280 Compute estimates of the main effects and interactions, and the sum of squares and P- value for each. a. b. Is the additive model appropriate? C. What…arrow_forward6. An economist studies the relationship between ahappiness index (y) and life expectancy (x) forindividual countries. Assume the SLR model.We know: n = 26, Y-hat = 0.98 + 0.08x , andthe 95% CI: 0.05 < β1 < 0.11.a) Does the evidence suggest a linearrelationship between the happiness indexand life expectancy? Explain.b) If appropriate, predict the happiness indexvalue for a country with a life expectancy of 75.arrow_forwardThe article "Factorial Experiments in the Optimization of Alkaline Wastewater Pretreatment" (M. Prisciandaro, A. Del Borghi, and F. Veglio, Industrial Engineering and Chemistry Research, 2002:5034-5041) presents the results of an experiment to investigate the effects of the concentrations of sulfuric acid (H,So,) and calcium chloride (CaCl,) on the amount of black mud precipitate in the treatment of alkaline wastewater. There were three levels of each concentration, and two replicates of the experiment were made at each combination of levels. The results are presented in the following table (all measurements are in units of kg/m). H;5O, CaCl, 15 Precipitate 100.2 110 98.2 110 30 175.8 216.5 176.2 110 45 206.0 123 15 110.5 105.5 123 30 45 184.7 189.0 123 234.0 222.0 136 15 106.5 107.0 136 30 1817 189.0 136 45 211.8 201.3 a Construct an ANOVA table. You may give ranges for the P-values. b. Is the additive model plausible? Explain. c. Can you concude that H,S0, concentration affects the…arrow_forward
- PCBs and Pelicans. Polychlorinated biphenyls (PCBs), industrial pollutants, are known to be carcinogens and a great danger to natural ecosystems. As a result of several studies, PCB production was banned in the United States in 1979 and by the Stockholm Convention on Persistent Organic Pollutants in 2001. One study, published in 1972 by R. W. Risebrough, is titled ‘‘Effects of Environmental Pollutants Upon Animals Other Than Man’’ (Proceedings of the 6th Berkeley Symposium on Mathematics and Statistics, VI, University of California Press, pp. 443–463). In that study, 60 Anacapa pelican eggs were collected and measured for their shell thickness, in millimeters (mm), and concentration of PCBs, in parts per million (ppm). Following is a relative-frequency histogram of the PCB concentration data.arrow_forwardDuring the spring of 1999, many fuel storage facilities in Serbia were destroyed by bombing. As a result, significant quantities of oil products were spilled and burned,resulting in soil pollution. The article “Mobility of Heavy Metals Originating from Bombing of Industrial Sites” (B. Škrbić, J. Novaković, and N. Miljević, Journal of Environmental Science and Health, 2002:7–16) reports measurements of heavy metal concentrations at several industrial sites in June 1999, just after the bombing, and again in March of 2000. At the Smederevo site, on the banks of the Danube River, eight soil specimens taken in 1999 had an average lead concentration (in mg/kg) of 10.7 with a standard deviation of 3.3. Four specimens taken in 2000 had an average lead concentration of 33.8 with a standard deviation of 0.50. Find a 95% confidence interval for the increase in lead concentration between June 1999 and March 2000.arrow_forwardThe antibiotic gentamicin sulphate is often blended with acrylic bone cement to help prevent infection following joint replacement surgery. The article "Incorporation of Large Amounts of Gentamicin Sulphate Into Acrylic Bone Cement: Effect on Handling and Mechanical Properties, Antibiotic Release, and Biofilm Formation" (N. Dunne, P. MCAfee, et al., Journal of Engineering in Medicine, 2008:355-365) presents a study of the effect of the amount of antibiotic added on various properties of the cement. Following are measurements of the setting time of the cement, for six levels of antibiotic amount, and three replications per level. The measurements are consistent with means and standard deviations presented in the article. Antibiotic per 40 g Cement Setting Time (min) 0g 0.58 1g 12.7 14.1 13.2 13.5 14.5 14.6 12.7 13.4 13.2 12.7 13.6 14.1 13.4 13.5 14.3 14.5 13.5 14.9 Construct an ANOVA table. You may give a range for the P-value. Can you conclude that there are differences among the mean…arrow_forward
- Cortisol is a hormone that plays an important role in mediating stress. There is a growing awareness that exposure of outdoor workers to pollutants may impact cortisol levels. The article "Plasma Cortisol Concentration and Lifestyle in a Population of Outdoor Workers" (International Journal of Environmental Health Res., 2011: 62-71) reported on a study involving three groups of police officers: 1. Traffic Police (TP) 2. Drivers (D) 3. Other Duties (0) Here is summary data on cortisol concentration (ng/ml) for a subset of the officers who neither drank nor smoked. Group Sample Size Mean SD TP 174.7 50.9 160.2 37.2 153.5 45.9 44 44 44 Assuming that the standard assumptions for one-way ANOVA are satisfied, carry out a test at significance level 0.05 to decide whether the true average cortisol concentration is different for the three groups. If any differences exist, state which groups are different.arrow_forwardThe article “Advances in Oxygen Equivalence Equations for Predicting the Properties of Titanium Welds” (D. Harwig, W. Ittiwattana, and H. Castner, The Welding Journal, 2001:126s–136s) reports an experiment to predict various properties of titanium welds. Among other properties, the elongation (in %) was measured, along with the oxygen content and nitrogen content (both in percent). The following MINITAB output presents results of fitting the model The regression equation is Elongation = 46.80 – 130.11 Oxygen – 807.1 Nitrogen + 3580.5 Oxy*Nit Predictor Coef SE Coef T P Constant 46.802 3.702 12.64 0.000 Oxygen – 130.11 20.467 – 6.36 0.000 Nitrogen – 807.10 158.03 – 5.107 0.000 Oxy*Nit 3580.5 958.05 3.737 0.001 S = 2.809 R-Sq = 74.5% R-Sq(adj) = 72.3% Analysis of Variance Source DF SS MS F P Regression 3 805.43 268.48 34.03 0.000 Residual Error 35 276.11 7.89 Total 38 1081.54 a. Predict the…arrow_forwardOpen water oil spills, such as the Deepwater Horizon spill of 2010, can wreak terrible consequences on the environment and be expensive to clean up. Many physical and biological methods have been developed to recover oil from water surfaces. In the article “Capacity of Straw for Repeated Binding of Crude Oil from Salt Water and Its Effect on Biodegradation” (J. Hazard. Toxic Radioact. Waste, 2012: 75–78), researchers examined how wheat straw could be used to extract crude oil from a water surface. An experiment was conducted in which crude oil (0 to 16.9 g) was added to 100 mL of saltwater in separate Petri dishes. Wheat straw (2 g) was then added to each dish and all dishes were shaken at 70 rpm overnight. The following data read from a graph is based on the amount of oil added (in g) and the corresponding amount of oil recovered (in g) from wheat straw. a. For each observation, determine the percentage of oil recovery by wheat straw. Is this percentage relatively…arrow_forward
- A study examining the effect of caffeine on squat and bench press 1-repitition maximum requires each participant perform three experimental trials: caffeine at a dose of 3 mg/kg; caffeine at a dose of 6 mg/kg; and placebo. Neither the investigator nor the participant knows which treatment they will receive during the experimental trials. This is an example of which element(s) of a strong research design: O Cross-over O Placebo-controlled O Double-blind O All the abovearrow_forwardThe article "Effect of Granular Subbase Thickness on Airfield Pavement Structural Response" (K. Gopalakrishnan and M. Thompson, Journal of Materials in Civil Engineering, 2008:331-342) presents a study of the effect of the subbase thickness (in mm) on the amount of surface deflection caused by aircraft landing on an airport runway. Two landing gears, one simulating a Boeing 747 aircraft, and the other a Boeing 777 aircraft, were trafficked across four test sections of runway. The results are presented in the following table. Section 3 4 Boeing 747 Boeing 777 4.01 3.87 3.72 3.76 4.57 4.48 4.36 4.43 Can you conclude that the mean deflection is greater for the Boeing 777?arrow_forwardResearchers have noted a decline in cognitive functioning as people age (Bartus, 1990). However, the results from other research suggest that the antioxidant in foods such as blueberries can reduce and even reverse those age-related declines, at least in laboratory rats (Joseph,et al.,1999). Based on these results, one might theorize that the same antioxidants might benefit elderly humans. Suppose a researcher is interested in testing this theory. The researcher obtains a sample of n = 16 adults who are older than 65, and gives and gives each participant a daily dose of blueberry supplement that is very high in antioxidants. After taking the supplement for 6 months, the participants are given a standardized cognitive skills test and produce a mean score of M = 50.2. For the general population of elderly adults scores on the test average μ =45 and form a normal distribution with a σ = 9. Can the researchers conclude that the supplement significantly increases cognitive skills? Use a…arrow_forward
- MATLAB: An Introduction with ApplicationsStatisticsISBN:9781119256830Author:Amos GilatPublisher:John Wiley & Sons IncProbability and Statistics for Engineering and th...StatisticsISBN:9781305251809Author:Jay L. DevorePublisher:Cengage LearningStatistics for The Behavioral Sciences (MindTap C...StatisticsISBN:9781305504912Author:Frederick J Gravetter, Larry B. WallnauPublisher:Cengage Learning
- Elementary Statistics: Picturing the World (7th E...StatisticsISBN:9780134683416Author:Ron Larson, Betsy FarberPublisher:PEARSONThe Basic Practice of StatisticsStatisticsISBN:9781319042578Author:David S. Moore, William I. Notz, Michael A. FlignerPublisher:W. H. FreemanIntroduction to the Practice of StatisticsStatisticsISBN:9781319013387Author:David S. Moore, George P. McCabe, Bruce A. CraigPublisher:W. H. Freeman