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?
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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_forwardA sample of ore is found to be 0.0022% gold and 0.059% silver. What is the percentage of matter in the ore that is neither gold or silver?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
- The amount of pollution produced by cars was measured for cars using gasoline containing different amounts of lead. A. Independent B. Dependentarrow_forwardRadon is a colorless, odorless gas that is naturally released by rocks and soils and may concentrate in tightly closed houses. Since 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 30 radon detectors in a chamber where they were exposed to 105 picocuries per liter (pCi/l) of radon over 3 days. The sample average reading from the 30 radon detectors was 102.87 pCi/l and the sample standard deviation was 4.9 pCi/l. Are the researchers able to conclude at the 5% significance level that the average reading differs from the true value of 105? To test: Ho: (Click to select) (Click to select) : vs. Ha: ( (Click to select) : (Click to select) Test Statistic (Round to three decimals): (Click to select) p-value (Round to three decimals): Conclusion: At a =[ (Click to select) : since p-value (Click to select) a. We have (Click to…arrow_forwardRadon is a colorless, odorless gas that is naturally released by rocks and soils and may concentrate in tightly closed houses. Since 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 30 radon detectors in a chamber where they were exposed to 105 picocuries per liter (pCi/l) of radon over 3 days. The sample average reading from the 30 radon detectors was 102.87 pCi/ and the sample standard deviation was 4.9 pCiA. Are the researchers able to conclude at the 5% significance level that the average reading differs from the true value of 105? To test: Ho u vs. Ha Test Statistic (Round to three decimals) (Click to select) p-value (Round to three decimals) Conclusion: At a = evidence to conclude that the Click to select) pCiA. KClick to select) since p-value (Click to select) M a. We have KClick to select) V reading (Click to…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
- Pineal Gland Study. Dr. Marquez hypothesized that fluoride had a deleterious effect on the pineal gland, which helps with sleeping. He measured the amount of fluoride in Americans and compared it to the fluoride level in Europeans, where its use in drinking water has been banned. He knew from reading the literature that the average fluoride level in Europeans was 40 parts per million (ppm). He collected a representative sample of 625 Americans and found that their fluoride level was 60 ppm with a standard deviation of 250 ppm. What is the value of the z-test statistic?arrow_forwardANSWER C AND D ONLYarrow_forwardA botanist grew 24 pepper plants on the same greenhouse bench. After 21 days, she measured the total stem length (cm) of each plant, and obtained the following values: 10.1 10.9 11.8 12.2 12.2 12.5 13.2 13.2 13.5 What terms can be used to classify the variable of interest in this study? 9.8 12.1 13.1 O A. Categorical - Nominal OB. Categorical - Ordinal OC. Numeric - Continuous OD. Numeric - Discrete 11.3 12.3 13.4 11.9 12.6 13.5 12.0 12.7 13.6 12.0 13.0 14.1arrow_forward
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