Below find a set of times (in weeks) tohospitalization for persons with a diagnosis ofschizophrenia who have been randomized tostandard therapy (Trt=0) or a new drugtreatment (Trt=1). A plus sign indicates censoringthat we will assume to be independent ofdisease.Trt=0: 6 8 11+ 13 16 16 19 21+ 22+ 28 28+ 29 3135 40+ 41+ 41+ 59+ 86+ 132+ Trt=1:6 9+ 9 1011+ 12+ 13+ 17+ 18 19+ 19 20+ 22 24 28+ 31 43+48 51+ 57+1. Assuming a constant hazard (i.e. risk ofhospitalization) in weeks 11 through 20, theestimated hazard of hospitalization for the newdrug group (Trt=1) during this period is:a. 2/129 person-weeksb. 5/129 person-weeksc. 7/129 person-weeksd. 2/169 person-weekse. 7/169 person-weeks

Given the set of times (in weeks) to hospitalization for persons with a diagnosis of schizophrenia…

Answered: Below find a set of times (in weeks) to…

MATLAB: An Introduction with Applications

6th Edition

ISBN:9781119256830

Author:Amos Gilat

Publisher:Amos Gilat

Chapter1: Starting With Matlab

Section: Chapter Questions

Problem 1P

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A study was conducted to determine if lung cancer altered levels of surfactant in the alveoli of the lung. Seven healthy subjects in the study yielded the following data on surfactant levels: 18, 12, 15, 15, 16, 9, 17. Seven lung cancer patients yielded the following results: 16, 8, 7, 15, 11, 12, 9. Do these data indicate a difference in the surfactant level with cancer? Let α = 0.05. Give the p-value.
A new screening test for Lyme disease is developed for use in the general population. The sensitivity and specificity of the new test are 60% and 70%, respectively. Five hundred people are screened at a clinic during the first year the new test is implemented. Assume the true prevalence of Lyme disease among clinic attendees is 10%. Calculate the predictive value of a positive test.
According to a CCH Unscheduled Absence survey 9 of small According to a CCH Unscheduled Absence survey, 9% of small businesses use telecommuting of workers in an effort to reduce unscheduled absenteeism. This proportion compares to 6% for all businesses. Is there really a significant difference between small businesses and all businesses on this issue? Use these data and an alpha of .10 to test this question. Assume that there were 780 small businesses and 915 other businesses in this survey. According to a CCH Unscheduled Absence survey 9 of small
Citrus Rental is a popular car rental agency that has a history of having too few cars available, so that its available cars are overdriven. The mean monthly mileage over the years for Citrus cars has been about 1550 miles per month. Recently, though, Citrus purchased thousands of new cars, and the company claims that the average mileage of its cars is now less than in the past. To test this, a random sample of 13 recent mileages of Citrus cars was taken. The mean of these 13 mileages was 1425 miles per month, and the standard deviation was 209 miles per month. Assume that the population of recent monthly mileages of Citrus cars is normally distributed. At the 0.10 level of significance, can it be concluded that the mean recent monthly mileage, μ, of Citrus cars is less than 1550 miles per month? Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places and round your answers as specified in the table. (If necessary,…
A study of parental empathy for sensitivity cues and baby temperament (higher scores mean more empathy) was performed. Let x, be a random variable that represents the score of a mother on an empathy test (as regards her baby). Let x, be the empathy = 68.36. Another random sample of 31 fathers gave score of a father. A random sample of 37 mothers gave a sample mean of x, X, = 60.06. Assume that o, = 11.55 and o, = 11.45. (a) Let u, be the population mean of x, and let u, be the population mean of x,. Find a 99% confidence interval for u, - Hz. (Round your answers to two decimal places.) lower limit upper limit (b) Examine the confidence interval and explain what it means in the context of this problem. Does the confidence interval contain all positive, all negative, or both positive and negative numbers? What does this tell you about the relationship between average empathy scores for mothers compared with those for fathers at the 99% confidence level? Because the interval contains only…
Citrus Rental is a popular car rental agency that has a history of having too few cars available, so that its available cars are overdriven. The mean monthly mileage over the years for Citrus cars has been about 1600 miles per month. Recently, though, Citrus purchased thousands of new cars, and the company claims that the average mileage of its cars is now less than in the past. To test this, a random sample of 16 recent mileages of Citrus cars was taken. The mean of these 16 mileages was 1517 miles per month, and the standard deviation was 233 miles per month. Assume that the population of recent monthly mileages of Citrus cars is normally distributed. At the 0.05 level of significance, can it be concluded that the mean recent monthly mileage, μ, of Citrus cars is less than 1600 miles per month? Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places and round your answers as specified in the table. (If necessary,…
A new medication is being developed to treat severe nausea and vomiting among chemotherapy patients. The information below was generated from a small sample size (n = 11) and shows the number of times a chemotherapy patient vomited both before and after treatment due to the side effects of chemotherapy. Set up and interpret the results of a sign test at the alpha equals .05 level to determine if there is a difference in symptoms before and after treatment. Chemotherapy Patient Before Treatment After Treatment Difference Sign 1 9 3 2 12 5 3 14 7 4 9 4 5 8 2 6 11 3 7 15 7 8 12 8 9 7 8 10 9 5 11 8 7 A) We fail to reject H0, which states the median difference in the number of vomiting episodes in a day before and after treatment are equal because 1 is less or equal to critical value 1 for a sign test…
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You believe that your morning commute to UCLA is decreasing every week. You record thetime of 7 commutes (one for each day of the week) (in minutes) for the a one-week block and thenthe following one-week block. * Calculations have been done for you: the sample mean difference is -1.714 and the sample standarddeviation is 2.984. Conduct a hypothesis test at the α = 0.15 level. The mean difference calculated as the the first one-week block minus the second one-week block. That is to say week one minus week two. a. Set up the null and alternative hypothesis (using mathematical notation/numbers and interpretthem in context of the problem) b. Calculate the test statistic for the test from part a

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