this is a timed 2 hour assignment . I can provide an example of one . I need Bolla to do this assginment. Last time you assigned to a random person who made me fail it with 40%.
1. In a clinical trial to study if an experiment drug can lower diastolic blood pressure, 780 participants suffering from Hi BP were randomly assigned to one of three groups. Over a one-month period, the first group received a low dosage of the experimental drug, the second group received a high dosage of the drug, and the third group received a placebo. Neither the patients nor those analyzing the results knew what type of treatment each patient received. The diastolic pressure (in mmHg) of each participant was measured at the beginning and at the end of the period and the change in blood pressure was recorded. a) Describe the 5 W’s and How. If the information is given, if the information is not given, stat that it is not specified. (6 marks) b) List the variables, indicate whether each variable is categorical or quantitative. If the variable is quantitative, give the units. (4 marks) 2. The five-number summary for midterm scores (number of points; the maximum possible score was 50 points)from an intro stat class is: MINQ1MedianQ3Max 16.5323943.548.5 a) Would you expect the mean midterm score of all students who took the midterm to be higher or lower than the median? (2 marks) b) Based on the five-number summary, are any of the midterm scores outliers? Explain (4 marks) 3. The National Sleep Foundation reported a moderately strong positive association between the number of hours of sleep a person gets and the person’s ability to listen, learn, and solve problems. a) Explain in the context of this problem what “positive association” means. (2 marks) b) Hoping to improve academic performance, a professor recommends allowing students to take a nap prior to taking midterms and finals. Discuss the professors’ recommendation. (4 marks) 4. A college’s job placement office collected data about student’s GPA and the salaries they earned in their first jobs after graduation. The correlation between the two variables was r=0.72. The association appeared to be linear in the scatter point. The regression equation was: Salary = 2,830 + 15,3000 GPA a. Interpret the slope in the context of the problem. (4 marks) b. You have just graduated with a GPA of 3.5 . What starting salary should you expect? (3 marks) c. What percentage of the variation in starting salaries is explained by the regression on GPA? (3 marks) 5. Administrators at a hospital are concerned about the possibility of drug abuse by people who work there. They decided to check on the extent of the problem by having a random sample of the employees undergo a drug test. a. Define the population and the parameter of interest in context. (3 marks) b. Describe a method that you would use to collect your sample. Make sure to name the sampling method you would use. (3 marks) c. There are four employee classifications: doctors, medical staff (nurses, technicians, etc. ) office staff, and support staff (custodians, maintenance, etc.). Describe how knowing about these classifications would modify your plan in part (b) and why. (4 marks) 6. Test on adverse reactions to a new drug yielded the results given in the table below: Treatment Drug Placebo Total Headaches 11 7 18 No Headaches 73 91 164 TOTAL 84 98 182 Is there evidence that reaction is independent of the type of treatment? Test an appropriate hypothesis at OC =0.05. Give statistical evidence to support your conclusion. (10 marks) You do not need to check the model assumptions. 7. Suppose the household incomes for Kamloops are normally distributed with mean $62,000 and standard deviation $6,800. a) If 50 households are randomly selected, find the probability that their mean household income is below $65,000. (6 marks) b) If households with the bottom 10% of incomes qualify for a special tax cut, what is the maximum income required to qualify for the tax cut? (4 marks) 8. A state’s department of education reports that 12% of the high school students in that state attend private high school. The state university wonders if the percentage is the same in their applicant pool. Admissions officers plan to check a random sample of the over 10,000 applications on file to estimate the percentage of students applying for admission who attend private schools. a. They select a random sample of 500 applications and find that 52 of those students attend private school. Check the conditions required for inference. (3 marks) b. Create the 95% confidence interval. (6 marks) c. Interpret the confidence interval in this context. ( 3 marks) d. Should the admissions officers conclude that the percentage of private school students in their applicant pool is lower than the statewide enrollment rate of 12%. Explain. (2 marks) 9. A consumer group was interested in comparing the operating time of a cordless toothbrushes manufactured by two different companies. Group member took random samples of 25 toothbrushes from Company A and 20 from Company B. Each was charged overnight and the number of hours of use before needing to be recharged was recorded. Company A toothbrushes operated for an average of 119.7 hours with a standard deviation of 1.74 hours; Company B toothbrushes operated for an average of 120.6 hours with a standard deviation of 1.72 hours. Do these samples indicate that Company B toothbrushes operate more hours on average than Company A toothbrushes? Test at a=0.05. (12 marks) You do not need to check the model assumptions. 10. A survey of an introductory statistics class asked students whether or not they ate breakfast the morning of the survey. The results are as follow: Breakfast Yes No Total Male 66 66 132 Female 125 74 199 Total 191 140 331 a. What is the probability that a randomly selected student is female? (2 marks) b. what is the probability that a randomly selected student is a female or ate breakfast? (3 marks) c. What is the probability that a randomly selected student is a female and did not eat breakfast? (2 marks) d. What is the probability that a randomly selected student is female, given that the student ate breakfast? (2.5 marks) e. What is the probability that a randomly selected student ate breakfast, given that the student is a female? (2.5 marks)