Frailty, Advanced Statistics

Assignment Help:

A term usually used for unobserved individual heterogeneity. Such variation is of main concern in the medical statistics particularly in the analysis of the survival times where hazard functions can be strongly influenced by the selection effects operating in the population. There are several possible sources of this heterogeneity, the most apparent of which is that it reflects the biological differences, so that, for instance, some individuals are born with the weaker heart, or a genetic disposition for cancer. A further prospect is that the heterogeneity happens from the occured weaknesses which result from the stresses of life. Failure to take account of this kind of variation might often obscure comparisons between groups, for instance, by measures of relative risk. A simple model which attempts to permit for the variation between individuals is given as follows


1270_fraility.png 


where Z is the quantity specific to an individual, considered as the random variable over the population of individuals, and the base rate is denoted by λ(t) . What is observed in a population for which this type of model holds is not the individual hazard rate but the net result for several individuals with different values of Z.

 


Related Discussions:- Frailty

Mantel haenszel estimator, Mantel Haenszel  estimator is  an estimator o...

Mantel Haenszel  estimator is  an estimator of assumed common odds ratio in the series of two-by-two contingency tables arising from the different populations, for instance, occ

Residual calculation, Regression line drawn as y= c+ 1075x ,when x was2, an...

Regression line drawn as y= c+ 1075x ,when x was2, and y was 239,given that y intercept was 11. Calculate the residual ?

Degenerate distributions, The special cases of the probability distribution...

The special cases of the probability distributions in which the random variable's distribution is concentrated at one point only. For instance, a discrete uniform distribution when

Paired samples, Paired samples are the two samples of the observations wit...

Paired samples are the two samples of the observations with the characteristic feature with each of the observation in one sample have only one matching observation in the other s

Collective risk models, Collective risk models : The models applied to insu...

Collective risk models : The models applied to insurance portfolios which do not create direct reference to the risk characteristics of individual members of the portfolio when des

Independent or Dependent variable, Whats the independent variable in the fo...

Whats the independent variable in the following sentence? -1) In a drug prevention program for boys and girls, will family-participation result in effective drug use reduction?

Define least significant difference test, Least significant difference test...

Least significant difference test is an approach to comparing a set of means which controls the family wise error rate at some specific level, let's assume it to be α. The hypothe

Minimization, Minimization is the method or technique for allocating patie...

Minimization is the method or technique for allocating patients to the treatments in clinical trials which is usually the acceptable alternative to random allocation. The procedur

Density estimation, Procedures for estimating the probability distributions...

Procedures for estimating the probability distributions without supposing any particular functional form. Constructing the histogram is perhaps the easiest example of such type of

Coefficient of concordance, Coefficient of concordance : The coef?cient is ...

Coefficient of concordance : The coef?cient is taken in use to assess the agreement among m raters ranking n individuals according to some of the speci?c characteristic. Which can

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