A study was designed to assess the time to first exit-site infection (in months) in patients with renal insufficiency. In this study, 43 patients utilized a surgically placed catheter and 76 patients utilized a percutaneous placement of their catheter. See Section 1.4 (K&M) for more details. Data from this study is presented in Table 1.2.(a) Give a sensible formulation for the time-to-event problem in this study. Define the event of interest, time origin, and time scale.(b) What is the percentage of censored observations among patients whose catheter was placed surgically?(c) The investigators are interested in testing if there is a difference in the time to cutaneous exit-site infection between patients whose catheter was placed surgically and patients who had their catheters placed percutaneously. Do you think you can answer this question using a two-sample t-test? Provide justifications for your answer.answer a,b, & c In a study (Nahman et al., 1992) designed to assess the time to first exit-site infection (in months) in patients with renal insufficiency, 43 patientsutilized a surgically placed catheter (Group 1), and 76 patients utilizeda percutaneous placement of their catheter (Group 2). Cutaneous exit-site infection was defined as a painful cutaneous exit site and positivecultures, or peritonitis, defined as a presence of clinical symptoms,elevated peritoneal dialytic fluid, elevated white blood cell count (100white blood cells/µl with >50% neutrophils), and positive peritonealdialytic fluid cultures. The data appears in Table 1.2.TABLE 1.2Times to infection (in months) of kidney dialysis patients with different catheter-ization proceduresSurgically Placed CatheterInfection Times: 1.5, 3.5, 4.5, 4.5, 5.5, 8.5, 8.5, 9.5, 10.5, 11.5, 15.5, 16.5, 18.5, 23.5, 26.5Censored Observations: 2.5, 2.5, 3.5, 3.5, 3.5, 4.5, 5.5, 6.5, 6.5, 7.5, 7.5, 7.5, 7.5, 8.5, 9.5,10.5, 11.5, 12.5, 12.5, 13.5, 14.5, 14.5, 21.5, 21.5, 22.5, 22.5, 25.5, 27.5Percutaneous Placed CatheterInfection Times: 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 2.5, 2.5, 3.5, 6.5, 15.5Censored Observations: 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 1.5, 1.5, 1.5, 1.5, 2.5,2.5, 2.5, 2.5, 2.5, 3.5, 3.5, 3.5, 3.5, 3.5, 4.5, 4.5, 4.5, 5.5, 5.5, 5.5, 5.5, 5.5, 6.5, 7.5, 7.5,7.5, 8.5, 8.5, 8.5, 9.5, 9.5, 10.5, 10.5, 10.5, 11.5, 11.5, 12.5, 12.5, 12.5, 12.5, 14.5, 14.5,16.5, 16.5, 18.5, 19.5, 19.5, 19.5, 20.5, 22.5, 24.5, 25.5, 26.5, 26.5, 28.5

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Answered: A study was designed to assess the time…

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 designed to assess the time to first exit-site infection (in months) in patients with renal insufficiency. In this study, 43 patients utilized a surgically placed catheter and 76 patients utilized a percutaneous placement of their catheter. See Section 1.4 (K&M) for more details. Data from this study is presented in Table 1.2.

(a) Give a sensible formulation for the time-to-event problem in this study. Define the event of interest, time origin, and time scale.

(b) What is the percentage of censored observations among patients whose catheter was placed surgically?

(c) The investigators are interested in testing if there is a difference in the time to cutaneous exit-site infection between patients whose catheter was placed surgically and patients who had their catheters placed percutaneously. Do you think you can answer this question using a two-sample t-test? Provide justifications for your answer.

answer a,b, & c