please help with following questions:-
It was known that a toxic material was dumped in a river leading into a large salt water commercial fishing area. Civil engineers studied the way the water carried the toxic material by measuring the amount of the material (in parts per million) found in oysters harvested at three different locations, ranging from the estuary out into the bay where the majority of commercial fishing was carried out. The resulting data are given below: Site 1 Site 2 Site 3 15 19 22 26 15 20 10 24 20 26 26 29 11 15 28 17 21 13 24 26 15 18 (=) Test whether there is a significant difference in the average parts per million of toxic material found in oysters harvested at the three sites. Use o = .05. (b) Would the means be significantly different at the .01 level of significance? (Use a computer package to find the P value.) (c) Do your answers in parts (a) and (b) contradict each other? Justify your answer.As landfills begin to fill up and land for such operations becomes more scarce, recycling will become more and more necessary. Some fast-food chains have become aware of this problem and are beginning to use biodegradable packaging or to recycle their packaging material. A study is conducted to investigate the amount of money received per year for recycled goods by various sized businesses. These data, in thousands of dollars, are obtained (based on figures in "New Ways to Take Out the Trash," Tom Andel, Transportation and Distribution, May 1993): Company Size 101-250 251-500 Over 500 employees employees employees 3.5 3.8 13.4 14.1 9.0 10.5 3.4 3.0 - 14,0 14.7 10.3 10.7 3.7 2.8 14.5 15.0 10.1 9.5 3.3 3.2 14.7 13.6 10.6 11.2 20 3.0 15.2 143 104 9.7 2.6 41 15.5 14.6 10.5 10.0 3.5 4.0 14.2 14.8 103 11.3 4.2 49 15.3 15.6 10.7 11.8 ( ) Construct stem-and-leaf diagrams for each of these samples, and comment on the reasonableness of the normality assumption. (b) Estimate the variance of each of the populations from which these data are drawn, and comment on the reasonableness of the assumption of equal variances. (Do not try to test anything.) What has been done on this study to guard against a possible violation of the assumption of equal variances? (c) Test Ho: My = 12 = py. and report the P value of your test. What practical conclusion can be drawn?Scroll speed is an important consideration in the development of color graphics cards. A study is conducted to compare the time, in seconds, required to scroll one screen of WORD documents using five different color graphics cards with 24-inch monitors. The test conducted was a standard Hydra Quick Draw performance test. These data are obtained (based on information found in "Gauging Video Speed." MAC WORLD, June 1993, p. 28): Graphics cards C D 305 79.2 51.6 70.0 32.4 421 84.7 85.3 27.2 43.5 85.0 57.3 86.2 26.3 40.6 86.2 590 82.0 25,1 38.G JG.3 58.7 ST.2 38.2 32.1 83.1 6R.1 81.7 30.6 41.6 92.6 645 93.5 33.7 55 5 89.1 Use these data to test for equality of means. State your conclusion and report the P value of the test.A chemical engineer is studying a newly developed polymer to be used in removing toxic wastes from water. Experiments are conducted at five different temperatures. The response noted is the percentage of impurities removed by the treatment. Temperature II ITI IV 40 36 49 47 in 35 42 51 42 51 49 39 53 50 37 52 50 $1 40 50 $1 61 Test the null hypothesis of equal treatment means at the a = .05 level.A chemical engineer is studying a newly developed polymer to be used in removing toxic wastes from water. Experiments are conducted at five different temperatures. The response noted is the percentage of impurities removed by the treatment. Temperature II III IV 40 36 49 47 55 35 43 51 49 60 42 51 62 49 39 53 50 37 52 507 50 $1 40 50 $1 61 Use Bonferroni Ttests with a's 25 to compare all possible pairs of means. Report your results schematically by ordering the sample means from the smallest to the largest and underlining pairs that are not significantly different.A chemical engineer is studying a newly developed polymer to be used in removing toxic wastes from water. Experiments are conducted at five different temperatures. The response noted is the percentage of impurities removed by the treatment. Temperature II ITI IV 40 30 49 47 55 42 51 44 60 42 51 62 70 50 50 50 40 50 61 Write a contrast that can be used to compare the mean of population 5 to the aggregate of the other four means. Test the null hypothesis that this contrast assumes the value 0. Interpret your results in the context of this exercise.The design given in Table 13.12 is called a knight's move Latin square because one can get from each treatment type to another of the same type by making a knight's move as in the game of chess. The observed responses are given in parentheses in the table. Use these data to test Ho: P1.. = M2.. = My.. = /4.. at the a = .05 level. TABLE 13.12 A knight's move Latin square H II III IV A (3) B (42) C (9) D (5.3) C(1.0) D (5.6) A (3.8) B (4.3) B(45) A (3.5) D (5.7) C(1.4) D (5.5) C(8) B (3.9) A (3.7)In a study to compare the average gasoline mileage of three different grades of a particular brand of gasoline, two extraneous sources of variation are recognized. These are the driver and the type of car used in the road trials. Three drivers and three new automobiles are obtained. Table 13.13 gives the mileage obtained over each test run. Test the null hypothesis of equal means among grades of gasoline at the .05 level. TABLE 13.13 Gasoline mileage obtained controlling for driver and automobile type (A = regular, B = extra, C = super) Factor (auto type) 4 cylinder 6 cylinder 8 cylinder A (36.0) B (33.0) C (26.5) WN- B (36.5) C (33.5) A (25.0) C (38.0) A (32.5) B (26.0)A company is considering three word processors for use by their secretarial staff. All of them are acceptable, so the choice depends on which one is the easiest to learn. Since speed is affected by the type of article being produced and the learner, a Latin square design is used. The data obtained are given in Table 13.14. Test TABLE 13.14 Time required to learn various subroutines in a word processor (in hours) Factor (type of article) I prose II technical III report B (5) A (12) C (LO) C (12) B(LO) A (95) A (.8) C (1.7) B (9)Ozonization as a secondary treatment for effluent, following absorption by ferrous chloride, was studied for three reaction times and three pH levels. The study yielded the following results for effluent decline: Reaction time (minutes) PH level Effluent decline 20 7.0 23, 21. 22 90 16, 18, 15 10.5 14. 13. 16 40 7.0 20, 22, 19 90 14, 13, 12 10.5 12, 11, 10 7:0 21, 20. 19 9.0 13, 12, 12 10.5 11, 13, 12 State the null hypothesis to be tested first.Ozonization as a secondary treatment for effluent, following absorption by ferrous chloride, was studied for three reaction times and three ph levels. The study yielded the following results for effluent decline: Reaction time (minutes) PH level Effluent decline 20 7.0 23. 21. 22 9.0 16, 18, 15 10.5 14, 13. 16 40 7.0 20. 22, 19 90 14, 13, 12 10.5 12, 11, 10 7:0 21, 20. 19 9.0 13, 12, 12 10.5 11, 13, 12 Is it necessary to conduct one-way analyses on a level-by-level basis to be able to describe the nature of the differences in main effects? Explain.Decomposition of leaf packs was studied for four environments and three time lengths of exposure. The measurements were in grams of weight loss of leaf packs. The study yielded the following results: Time Environment 1 month 2 months 3 months 1 09 1.35 1.60 1.06 1.53 1.40 1.16 1.38 2.18 1.03 1.35 1.77 1.01 1.63 1.66 1.04 1.51 1.98 EA 0.90 1.60 1.73 1.03 1.72 1.76 Assuming the two-way classification model with fixed effects, write the model for this experiment and explain what each parameter represents in the context of this experiment.Decomposition of leaf packs was studied for four environments and three time lengths of exposure. The measurements were in grams of weight loss of leaf packs. The study yielded the following results: Time Environment 1 month 2 months 3 months EI 1.09 1.35 1.60 1.06 1.53 1.40 1.16 1.38 2.18 1.03 1.35 1.77 1.01 1.63 1.66 1.04 1.51 1.98 EA 0.90 1.60 1.73 1.03 1.72 1.76 Which combination of environment and time seems to yield the greatest decomposition of leaf packs?Each table given shows the theoretical treatment means for each of four treatments in each of three blocks. Graph these means in a manner similar to that of Fig. 13.3. In each case, decide whether or not there is interaction between blocks and treatments. Treatment Block A B C D (a) Treatment Block A B C D (b) Treatment Block A B C D (c) FIGURE 13.3 (a) Additive effects-no interaction (line segments are parallel); (b) interaction exists (line segments are not parallel). Block 1 Block I Block 2 Block 2 A C A Treatment Treatment (a) (6)
