Crude oil biodegradation. In order to protect their valuable resources, oil companies spend millions of dollars researching ways to prevent biodegradation of crude oil. The Journal of Petroleum Geology (April 201 0) published a study of the environmental factors associated with biodegradation in crude oil reservoirs. Sixteen water specimens were randomly selected from various locations in a reservoir on the floor of a mine. Two of the variables measured were (1) the amount of dioxide (milligrams/liter) present in the water specimen and (2) whether or not oil was present in the water specimen. These data are listed in the accompanying table in the next column. Construct a stem-and-leaf display for the dioxide data. Locate the dioxide levels associated with water specimens that contain oil. Highlight these data points on the stem-and-leaf display. Is there a tendency for crude oil to be present in water with lower levels of dioxide?
Want to see the full answer?
Check out a sample textbook solutionChapter 2 Solutions
Statistics for Business and Economics (13th Edition)
- What does the y -intercept on the graph of a logistic equation correspond to for a population modeled by that equation?arrow_forwardradon is a colorless, odorless gas that is naturally released by rocks and soils and may concentrate in tightly closed houses. because radon is slightly radioactive, there is some concern that it may be a health hazard. radon detectors are sold to homeowners worried about this risk, but the detectors may be inaccurate. university researchers placed 12 detectors in a chamber where they were exposed to 105 picocuries per liter (pci/l) of radon over 3 years. here are the readings given by the detectors:91.9 97.8 111.4 112.3 105.4 85.0 103.8 89.6 96.6 109.3 104.8 91.7 Assume (unrealistically) that you know that the standard deviation of readings for all detectors of this type is σ = 9. a. Give the 95% confidence interval for the mean reading μ for this type of detector. b. Is there significant evidence at the 5% level that the mean reading differs from the true value 105? State hypotheses and base a test on your confidence interval from (a). c. Calculate the power of this test against the…arrow_forwardIn a study of exhaust emissions from school buses, the pollution intake by passengers was determined for a sample of nine school buses used in the Southern California Air Basin. The pollution intake is the amount of exhaust emissions, in grams per person, that would be inhaled while traveling on the bus during its usual 1818‑mile trip on congested freeways from South Central LA to a magnet school in West LA. (As a reference, the average intake of motor emissions of carbon monoxide in the LA area is estimated to be about 0.0000460.000046 grams per person.) The amounts for the nine buses when driven with the windows open are given. 1.151.15 0.330.33 0.400.40 0.330.33 1.351.35 0.380.38 0.250.25 0.400.40 0.350.35 A good way to judge the effect of outliers is to do your analysis twice, once with the outliers and a second time without them. Give two 90%90% confidence intervals, one with all the data and one with the outliers removed, for the mean pollution intake among all school buses…arrow_forward
- Soil samples were collected at two areas surrounding an abandoned mine and analyzed for lead. At each area several samples were taken. The soil was extracted with acid, and the extract was analyzed using flame atomic absorption spectrometry. In Area A, Pb concentrations were 1.2, 1.0, 0.9, 1.4 mg/kg. In Area B, Pb concentrations were 0.7, 1.0, 0.5, 0.6, 0.4 mg/kg. Are these two areas significantly different from each other with Pb concentrations at 90% confidence level?arrow_forwardIn a study of processes used to remove impurities from cellulose goods, the following data resulted from a 24 experiment involving the desizing process. The four factors were enzyme concentration (A), PH (8), temperature (C), and time (0). Starch % by Weight Enzyme Temp. Time 1st Treatment (g/L) PH (1) 0.50 6.0 (°C) (hr) 60.0 2nd Repl. Repl. 6 9.72 13.50 а 0.75 6.0 60.0 6 9.80 14.04 b 0.50 7.0 60.0 6 10.13 11.27 ab 0.75 7.0 60.0 6 11.84 11.30 c 0.50 6.0 70.0 6 12.70 11.37 ac 0.75 6.0 70.0 6 11.96 12.05 bc 0.50 7.0 70.0 6 11.38 9.92 abc 0.75 7.0 70.0 6 11.80 11.14 d 0.50 6.0 60.0 8 13.15 13.00 ad 0.75 6.0 60.0 8 10.60 12.37 bd 0.50 7.0 60.0 8 10.37 12.00 abd 0.75 7.0 60.0 8 11.30 11.64 cd 0.50 6.0 70.0 8 13.05 14.55 acd 0.75 6.0 70.0 8 11.17 15.00 bcd 0.50 7.0 70.0 abcd 0.75 7.0 70.0 8 8 12.70 14.15 13.20 16.12 (a) Use Yates's algorithm to obtain sums of squares and the ANOVA table. (Round your answers to two decimal places.)arrow_forwardThree different corrosion-resistant coatings are being considered for use on iron pipes. Ten pieces of pipe are marked off in six equal segments. For each pipe, two segments received coating A, two received coating B, and the remaining two received coating C. The pipes were placed in a corrosive environment for a period of time; then the depth of the deepest pit (in mm) caused by corrosion was measured for each segment on each pipe. The effect of interest is the coating; the pipe is a blocking factor, and there were two replications on each pipe. The following sums of squares were calculated: sum of squares for blocks = 11.2, sum of squares for treatments = 4.8, sum of squares for interactions = 18.4, total sum of squares = 44.7. a) Construct an ANOVA table. You may give ranges for the P-values. b) Are the assumptions for a randomized complete block design satisfied? Explain. c) Does the ANOVA table provide evidence that mean pit depth differs among coatings? Explain.arrow_forward
- Scientists are looking at the effects of global warming on clutches of sea turtle hatchlings in different parts of the world. The data below has been collected: 1.Temperature of Incubation (in Kelvin) 2. Gender Group of Hatchling Clutch (0=0% male; 1= greater than 0% but less than or equal to 10% male; 2= greater than 10% but less than 20% male; 3= greater than 20% but less than or equal to 30% male and so on) 3. Number of hatched eggs 4. number of unhatched eggs 5. Location of Turtles (0=west North America; 1= west South America; 2= tropical regions of Pacific; 3= northwestern Atlantic; 4= Indian Ocean Which of the above variables are measured using a nominal scale, ordinal scale and ratio scale. (An answer can be none of variables) thank youarrow_forwardA study of Spring Peeper breeding yielded the results in the table below. Spring Peepers were bred in different temperature controlled environments. The concentration of dissolved oxygen was measured in each environment. Temperature of water (⁰C) Dissolved oxygen in freshwater (mg/L) Number of eggs hatched into tadpoles 8 10.0 80 8 12.0 100 8 13.5 120 8 16.0 150 15 8.0 600 15 9.5 1090 15 12.0 1700 15 14.0 2190 22 6.5 870 22 8.5 1450 22 10.5 1970 22 12.0 2450 29 5.5 110 29 7.0 210 29 9.0 400 29 11.0 500 Graph the data in the table linked in the description above. (Hint: You must identify the dependent variable and two independent variables.) You may complete your graph electronically or by hand (then take a photo of your graph). Upload your photo or electronic file. (COMPLETE IN ONE GRAPH).arrow_forwardThe department of zoology at the Virginia Polytechnic Institute and State University carried out a study to determine if there is a significant difference in the density of organisms in two different stations located in Cedar Run, a secondary river that is located in the river basin. Roanoke. Drainage from a sewage treatment plant and overflow from the Federal Mogul Corporation sedimentation pond enter the flow near the source of the river. The following data give the density measurements, in numbers of organisms per square meter, at the two different collecting stations. Number of organisms per square meter Station 1 Station 2 5030 2800 13700 4670 10730 6890 11400 7720 860 7030 2200 7330 4250 2810 15040 1330 4980 3320 11910 1230 8130 2130 26850 2190 17660 22800 1130 1690 With a significance level of 0.05, can we conclude that the densities are the same in the two…arrow_forward
- Is there a difference in the amount of airborne bacteria between carpeted and uncarpeted rooms? In an experiment, seven rooms were carpeted and seven were left uncarpeted. The rooms were similar in size and function. After a suitable period, the concentration of bacteria in the air was measured (in units of bacteria per cubic foot) in all of these rooms. The data and summaries are provided: x¯ s Carpeted rooms 184 22.0 Uncarpeted rooms 170 16.9 A 95% confidence interval for the difference in mean bacterial concentration in the air of carpeted rooms versus uncarpeted rooms (using the conservative value for the degrees of freedom) is: Select one: −11.7 to 39.7. −16.66 to 34.66. −7.47 to 31.47. −18.89 to 42.89.arrow_forwardAn article reported on a study in which each of 13 workers was provided with both a conventional shovel and a shovel whose blade was perforated with small holes. The authors of the cited article provided the following data on energy expenditure [kcal/kg(subject)/lb(clay)]. Worker: 2 4 5 6 Conventional: 0.0015 0.0015 0.0018 0.0022 0.001 0.0016 0.0028 Perforated: 0.0015 0.001 0.0019 0.0013 0.0011 0.0017 0.0024 Worker: 10 11 12 13 Conventional: 0.0021 0.0015 0.0014 0.0023 0.0017 0.002 Perforated: 0.0021 0.0013 0.0013 0.0017 0.0015 0.0013 n USE SALT Do these data provide convincing evidence that the mean energy expenditure using the conventional shovel exceeds that using the perforated shovel? Test the relevant hypotheses using a significance level of 0.05. (Use SALT to calculate the P-value. Use Hd = Hconventional - Hperforated Round your test statistic to one decimal place and your P-value to three decimal places.) t= df = p-value = State your conclusion. O we fail to reject H,. We have…arrow_forwardA medical student at a community college in city Q wants to study the factors affecting the systolic blood pressure of a person (Y). Generally, the systolic blood pressure depends on the BMI of a person (B) and the age of the person A. She wants to test whether or not the BMI has a significant effect on the systolic blood pressure, keeping the age of the person constant. For her study, she collects a random sample of 150 patients from the city and estimates the following regression function: Y= 15.50 +0.90B + 1.10A. (0.48) (0.35) The test statistic of the study the student wants to conduct (Ho: B, =0 vs. H4: B, #0), keeping other variables constant is. (Round your answer to two decimal places.) At the 5% significance level, the student will v the null hypothesis. Keeping BMI constant, she now wants test whether the age of a person (A) has no significant effect or a positive effect on the person's systolic blood pressure. So, the test statistic associated with the one-sided test the…arrow_forward
- Holt Mcdougal Larson Pre-algebra: Student Edition...AlgebraISBN:9780547587776Author:HOLT MCDOUGALPublisher:HOLT MCDOUGALLinear Algebra: A Modern IntroductionAlgebraISBN:9781285463247Author:David PoolePublisher:Cengage LearningGlencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw Hill