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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- In a study conducted in the Science Department of Faculty of Science, Technology and Human Development in a University; the researcher examined the influence of the drug succinylcholine on the circulation levels of androgens in the blood. Blood samples from wild, free-ranging deer were obtained via the jugular vein immediately after an intramuscular injection of succinylcholine using darts and a capture gun. Deer were bled again approximately 30 minutes after the injection and then released. The level of androgens at time of capture and 30 minutes later, measured in nanograms per milliliter (ng/ml), for 15 deers as in Table Q1. Assuming that the populations of androgen at time of injection and 30 minutes later are normally distributed:i) Find the average and standard deviation of this studyii)Determine the critical region of this problem.iii) Test at the 0.05 level of significance whether the androgen concentrations are altered after 30 minutes of restraint.arrow_forwardIn a study of the relationship between TV viewing and eating habits, a sample of 548 ethnically diverse students from Massachusetts was followed over a 19-month period.† For each additional hour of television viewed per day, the number of fruit and vegetable servings per day was found to decrease on average by 0.14 servings. (a) For this study, what is the response variable? location of studentsnumber of fruit and vegetable servings per day number of non fruit or vegetable servings per daynumber of hours of television viewed per dayyear What is the explanatory (predictor) variable? location of studentsnumber of fruit and vegetable servings per day number of non fruit or vegetable servings per daynumber of hours of television viewed per dayyear (b) Would the least squares regression line for predicting number of servings of fruits and vegetables using number of hours spent watching TV have a positive or negative slope? Justify your choice. The slope of the least squares…arrow_forwardAn experiment to determine if a migraine medication decreases a person's average number of monthly migraines is performed on 400 people who report they have several migraines a month. Researchers randomly assigned 200 people to the treatment group and 200 people to the control group. After the study, the researchers determined that 48 of the subjects in the treatment group and 28 of the subjects in the control group average fewer migraines per month. The data from the two groups are resampled 150 times, and the table shows the distribution of the differences of the proportions for the reconfigured treatment and control groups.arrow_forward
- Holt Mcdougal Larson Pre-algebra: Student Edition...AlgebraISBN:9780547587776Author:HOLT MCDOUGALPublisher:HOLT MCDOUGAL