Concept explainers
Treating circulatory disease: Angioplasty is a medical procedure in which an obstructed blood is widened. In some cases, a wire mesh tube, called a stent, is placed in the vessel to help it remain open. A study was conducted to compare the effectiveness of a bare metal stent with one that has been coated with a drug designed to prevent reblocking of the vessel. A total of 5320 patients received bare metal stents, and of these, 841 needed treatment for reblocking within a year. A total of 1120 received drug-coated stents, and 134 of them required treatment within a year. Can you conclude that the proportion of patients who needed retreatment is less for those who received drug-coated stents? Use the
Want to see the full answer?
Check out a sample textbook solutionChapter 11 Solutions
Elementary Statistics ( 3rd International Edition ) Isbn:9781260092561
- Cholesterol Cholesterol in human blood is necessary, but too much can lead to health problems. There are three main types of cholesterol: HDL (high-density lipoproteins), LDL (low-density lipoproteins), and VLDL (very low-density lipoproteins). HDL is considered “good” cholesterol; LDL and VLDL are considered “bad” cholesterol. A standard fasting cholesterol blood test measures total cholesterol, HDL cholesterol, and triglycerides. These numbers are used to estimate LDL and VLDL, which are difficult to measure directly. Your doctor recommends that your combined LDL/VLDL cholesterol level be less than 130 milligrams per deciliter, your HDL cholesterol level be at least 60 milligrams per deciliter, and your total cholesterol level be no more than 200 milligrams per deciliter. (a) Write a system of linear inequalities for the recommended cholesterol levels. Let x represent the HDL cholesterol level, and let y represent the combined LDL VLDL cholesterol level. (b) Graph the system of inequalities from part (a). Label any vertices of the solution region. (c) Is the following set of cholesterol levels within the recommendations? Explain. LDL/VLDL: 120 milligrams per deciliter HDL: 90 milligrams per deciliter Total: 210 milligrams per deciliter (d) Give an example of cholesterol levels in which the LDL/VLDL cholesterol level is too high but the HDL cholesterol level is acceptable. (e) Another recommendation is that the ratio of total cholesterol to HDL cholesterol be less than 4 (that is, less than 4 to 1). Identify a point in the solution region from part (b) that meets this recommendation, and explain why it meets the recommendation.arrow_forwardAngioplasty is a medical procedure in which an obstructed blood vessel is widened. In some cases, a wire mesh tube, called a stent, is placed in the vessel to help it remain open. A study was conducted to compare the effectiveness of a bare metal stent with one that has been coated with a drug designed to prevent reblocking of the vessel. A total of 5319 patients received bare metal stents, and of these, 848 needed treatment for reblocking within a year. A total of 1122 received drug-coated stents, and 142 of them required treatment within a year. Can you conclude that the proportion of patients who needed retreatment differs between those who received bare metal stents and those who received drug-coated stents? Let p1 denote the proportion of patients with bare metal stents who needed retreatment and p2 denote the proportion of patients with drug-coated stents who needed retreatment. Use the =α0.10 level of significance and the P -value method with the…arrow_forwardAngioplasty is a medical procedure in which an obstructed blood vessel is widened. In some cases, a wire mesh tube, called a stent, is placed in the vessel to help it remain open. A study was conducted to compare the effectiveness of a bare metal stent with one that has been coated with a drug designed to prevent reblocking of the vessel. A total of 5324 patients received bare metal stents, and of these, 838 needed treatment for reblocking within a year. A total of 1125 received drug-coated stents, and 141 of them required treatment within a year. Can you conclude that the proportion of patients who needed retreatment differs between those who received bare metal stents and those who received drug-coated stents? Let p1 denote the proportion of patients with bare metal stents who needed retreatment and p2 denote the proportion of patients with drug-coated stents who needed retreatment. Use the =α0.01 level of significance and the P -value method with the…arrow_forward
- After stinging its victim, the honeybee leaves behind the barbed stinger, poison sac and muscles that continue to pump venom into the wound. Visscher et al. (1996) compared the effects of two methods of removing the stinger left behind: scraping off with a credit card or pinching off with thumb and index finger. A total of 40 stings were induced on volunteers. Twenty were removed with the credit card method and 20 were removed with the pinching method. The size of the subsequent welt by each measurement came from two volunteers (both authors of the study), each of whom received one treatment 10 times on the one arm and the other treatment 10 times on the other arm. Pinching led to a slightly smaller average welt, but the difference between the methods was not significant. Does this study include a control group? Enter the number of the best answer choice from the options below Yes, the control group is the group receiving the credit card method. Yes, the control group is the…arrow_forwardAngioplasty is a medical procedure in which an obstructed blood vessel is widened. In some cases, a wire mesh tube, called a stent, is placed in the vessel to help it remain open. A study was conducted to compare the effectiveness of a bare metal stent with one that has been coated with a drug designed to prevent reblocking of the vessel. A total of 5313 patients received bare metal stents, and of these, 836 needed treatment for reblocking within a year. A total of 1111 received drug-coated stents, and 150 of them required treatment within a year. Can you conclude that the proportion of patients who needed retreatment is less for those who received drug-coated stents? Let p1 denote the proportion of patients with bare metal stents who needed retreatment and p2 denote the proportion of patients with drug-coated stents who needed retreatment. Use the a= 0.01 level of significance and the P -value method with the TI-84 Plus calculator.arrow_forwardWorkers in the office like to drink coffee during work. A doctor is concerned about this situation since the too much coffee consumption may result to long-term health problems. However, studies suggests that there is no risk in drinking three cups of coffee per day, which is about 250 mg of caffeine. The doctor wants to know if the amount of caffeine consumed by the workers is within tolerable limits. He randomly selected 20 students and found that they consume an average of 270 mg of caffeine each day with a standard deviation of 48 mg. Assume that the daily amount of caffeine consumed by students follow the normal distribution.1. Which of the following sets of hypotheses should be used in this study? A. Ho: μ = 250 vs. Ha: μ > 250 B. Ho: μ ≤ 250 vs. Ha: μ > 250 C. Ho: μ = 270 vs. Ha: μ > 270 D. Ho: μ = 270 vs. Ha: μ ≠ 270 2. Which of the following is(are) TRUE? I. The appropriate test procedure to answer the objective of the study is a…arrow_forward
- Sleep apnea is a condition in which the sufferers stop breathing momentarily while they are asleep. This condition results in lack of sleep and extreme fatigue during waking hours. A current estimate is that 10 million out of the 312.7 million Americans suffer from sleep apnea, or approximately 3.2%. A safety commission is concerned about the percentage of commercial truck drivers who suffer from sleep apnea. They do not have any reason to believe that it would be higher or lower than the population’s percentage. To test the claim that the percentage of commercial truck drivers who suffer from sleep apnea is not 3.2%, a simple random sample of 409 commercial truck drivers is examined by a medical expert, who concludes that 21 suffer from sleep apnea. Does this evidence support the claim that the percentage of commercial truck drivers who suffer from sleep apnea is not 3.2%? Use a 0.05 level of significance. Step 2 of 3 : Compute the value of the test statistic. Round your…arrow_forwardSleep apnea is a condition in which the sufferers stop breathing momentarily while they are asleep. This condition results in lack of sleep and extreme fatigue during waking hours. A current estimate is that 15 million out of the 312.7 million Americans suffer from sleep apnea, or approximately 4.8%. A safety commission is concerned about the percentage of commercial truck drivers who suffer from sleep apnea. They do not have any reason to believe that it would be higher or lower than the population’s percentage. To test the claim that the percentage of commercial truck drivers who suffer from sleep apnea is not 4.8%, a simple random sample of 339 commercial truck drivers is examined by a medical expert, who concludes that 7 suffer from sleep apnea. Does this evidence support the claim that the percentage of commercial truck drivers who suffer from sleep apnea is not 4.8%? Use a 0.05 level of significance. Step 3 of 3 : Draw a conclusion and interpret the decision.…arrow_forwardIs injecting medical cement effective in reducing pain for people who have suffered fractured vertebrae? A paper describes an experiment to compare patients who underwent vertebroplasty (the injection of cement) to patients in a placebo group who underwent a fake procedure in which no cement was actually injected. Because the placebo procedure was similar to the vertebroplasty procedure except for the actual injection of cement, patients participating in the experiment were not aware of which treatment they received. All patients were asked to rate their pain at three different times—3 days, 14 days, and 1 month after the procedure. Summary statistics are given in the accompanying table. Pain Intensity Vertebroplasty Group Placebo Group n = 76 n = 62 mean sd mean sd 3 days 4.2 2.8 3.9 2.9 14 days 4.3 2.9 4.5 2.8 1 month 3.9 2.9 4.6 3.0 Construct and interpret a 95% confidence interval for the difference in mean pain intensity 3 days after treatment for the…arrow_forward
- An oil company plans to add a chemical to its gasoline to make it burn more cleanly. The company conducts an experiment to see whether adding the chemical affects the gasoline mileage of cars using their gasoline. State the null hypothesis for the experiment. Adding the chemical increases gas mileage. Adding the chemical does not affect gasoline mileage. Adding the chemical affects gasoline mileage. Adding the chemical decreases gasoline mileage.arrow_forwardSleep apnea is a condition in which the sufferers stop breathing momentarily while they are asleep. This condition results in lack of sleep and extreme fatigue during waking hours. A current estimate is that 16.3 million out of the 312.7 million Americans suffer from sleep apnea, or approximately 5.2%. A safety commission is concerned about the percentage of commercial truck drivers who suffer from sleep apnea. They do not have any reason to believe that it would be higher or lower than the population’s percentage. To test the claim that the percentage of commercial truck drivers who suffer from sleep apnea is not 5.2%, a simple random sample of 380380 commercial truck drivers is examined by a medical expert, who concludes that 29 suffer from sleep apnea. Does this evidence support the claim that the percentage of commercial truck drivers who suffer from sleep apnea is not 5.2%? Use a 0.01 level of significance. Step 1 of 3 : State the null and alternative hypotheses for the test.…arrow_forwardSleep apnea is a condition in which the sufferers stop breathing momentarily while they are asleep. This condition results in lack of sleep and extreme fatigue during waking hours. A current estimate is that 10.9 million out of the 312.7 million Americans suffer from sleep apnea, or approximately 3.5 % . A safety commission is concerned about the percentage of commercial truck drivers who suffer from sleep apnea. They do not have any reason to believe that it would be higher or lower than the population's percentage. To test the claim that the percentage of commercial truck drivers who suffer from sleep apnea is not 3.5 % , a simple random sample of 308 commercial truck drivers is examined by a medical expert, who concludes that 19 suffer from sleep apnea. Does this evidence support the claim that the percentage of commercial truck drivers who suffer from sleep apnea is not 3.5 % ? Use a 0.05 level of significance. Step 1 of 3: State the null and alternative hypotheses for the test.…arrow_forward
- Glencoe Algebra 1, Student Edition, 9780079039897...AlgebraISBN:9780079039897Author:CarterPublisher:McGraw Hill