Different analyses of recurrent events data, Applied Statistics

Assignment Help:

Different analyses of recurrent events data:

The bladder cancer data listed in Wei, Lin, and Weissfeld (1989) is used in Example 54.8/49.8 of SAS to  illustrate different analyses of  recurrent events data using different models. The data consist of 86 patients with superficial bladder tumors, which were removed when the patients entered the study. Of these patients, 48 were randomized into the placebo group, and 38 were randomized into the thiotepa group. Many patients had multiple recurrences of  tumors during the study, and new tumors were removed at each visit. The data set contains the first four recurrences of the tumor for each patient, and each recurrence time was measured from the patient's entry time into the study. The data consist of the following eight variables:

  • Trt, treatment group (1 =placebo and 2=thiotepa)
  • Time, follow-up time
  • Number, number of initial tumors
  • Size, initial tumor size
  • Tl, T2, T3, and T4, times of the four potential recurrences of the bladder tumor. A patient with only two recurrences has missing values in T3  and T4.

Write the formulae of the proportional intensity and the proportional mean models estimated using appropriate SAS procedures (define the relevant variables, functions, parameters and identify the formulas for two models) using the covariate x (x=O for placebo and x=l for thiotepa). What are the variance estimates for these two regression estimates (specify their numerical values and the names of the estimators )?

Interpret the main results of the analyses of bladder cancer data under these two models. Are the key modeling assumptions of these analyses are justified (provide relevant plots with explanations)?


Related Discussions:- Different analyses of recurrent events data

Multiple correspondence analysis, Correspondence analysis is an exploratory...

Correspondence analysis is an exploratory technique used to analyze simple two-way and multi-way tables containing measures of correspondence between the rows and colulnns of an

Binomial and continuous model, Exercise: (Binomial and Continuous Model.) C...

Exercise: (Binomial and Continuous Model.) Consider a binomial model of a risky asset with the parameters r = 0:06, u = 0:059, d =  0:0562, S0 = 100, T = 1, 4t = 1=12. Note that u

Find the probability customers pay their bill in full, The proportion of Am...

The proportion of American Express credit-card holders who pay their credit card bill in full each month is 23%; the other 77% make only a partial or no payment. (a) In a random

Determine the regression equation, The file Midterm  Data.xls has a tab lab...

The file Midterm  Data.xls has a tab labeled "National Grid vs. Alcoa" which presents historical price data for two stocks.  Using the National Grid price as the X-value and the Al

Find the unbiased estimators for mean and variance matrix, Is the random ve...

Is the random vector (Trunk Space, Length, Turning diameter) of US car normally distributed? Why? If yes, find the unbiased estimators for the mean and variance matrix of (Trunk Sp

Active control equivalence studies (aces), Active Control Equivalence Studi...

Active Control Equivalence Studies (ACES) Clinical trials the field in which the object is easy to show that the new treatment is  as good as the existing treatment. Such type

Harmonic mean, The Harmonic Mean is based on the reciprocals of numbers ave...

The Harmonic Mean is based on the reciprocals of numbers averaged. It is defined as the reciprocal of the arithmetic mean of the reciprocal of the given individual observations. Th

E-mail messages should be answered quickly, Do people of different age grou...

Do people of different age groups differ in their response to e-mail messages? A survey by the Cent of the Digital Future of the University of Southern California reported that 70.

Choose the correct null hypotheses, For the following claim, find the null ...

For the following claim, find the null and alternative hypotheses, test statistic, P-value, critical value and draw a conclusion. Assume that a simple random sample has been selec

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd