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

Logistic regression - computing log odds without probabiliti, Please help w...

Please help with following problem: : Let’s consider the logistic regression model, which we will refer to as Model 1, given by log(pi / [1-pi]) = 0.25 + 0.32*X1 + 0.70*X2 + 0.

Exponential family, A family of the probability distributions of the form g...

A family of the probability distributions of the form given as   here θ is the parameter and a, b, c, d are the known functions. It includes the gamma distribution, normal dis

Sequencing of 4 machines, how to resolve sequencing problem if jobs 6 given...

how to resolve sequencing problem if jobs 6 given and 4 machines given. how to apply johnson rule for making to machines under this conditions. please give solution as soon as poss

Explain kurtosis, Kurtosis: The extent to which the peak of the unimodal p...

Kurtosis: The extent to which the peak of the unimodal probability distribution or the frequency distribution departs from its shape of the normal distribution, by either being mo

Statistical methods with financial applications, The marketing manager of H...

The marketing manager of Handy Foods Ltd. is concerned with the sales appeal of one of the company's present label for one of its products. Market research indicates that supermark

Chain-binomial models, Chain-binomial models : Models arising in mathematic...

Chain-binomial models : Models arising in mathematical theory of the quite infectious diseases, which postulate that at any stage in the epidemic there are a certain number of the

Bayesian network, Bayesian network : It is essentially an expert system in ...

Bayesian network : It is essentially an expert system in which the uncertainty is dealt with using the conditional probabilities and Bayes' Theorem. Formally such type of network c

SCATTER DIAGRAM, MEANING ,IMPORTANCE AND RELEAVANCE OF SCATTER DIAGRAM

MEANING ,IMPORTANCE AND RELEAVANCE OF SCATTER DIAGRAM

Zero-inflated poisson regression, Zero-inflated Poisson regression is  the...

Zero-inflated Poisson regression is  the model for count data with the excess zeros. It supposes that with probability p the only possible observation is 0 and with the probabilit

Central tendency, explain the graphical method of measure of central tenden...

explain the graphical method of measure of central tendency

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