User Tools

Site Tools


seminars:stat:160317

Differences

This shows you the differences between two versions of the page.

Link to this comparison view

Next revision
Previous revision
seminars:stat:160317 [2016/03/07 16:40] shangseminars:stat:160317 [2016/05/02 01:46] (current) aleksey
Line 1: Line 1:
 +<WRAP centeralign>##Statistics Seminar##\\ Department of Mathematical Sciences</WRAP>
  
 +~~META:title =March 17, 2016~~
 +<WRAP 70% center>
 +^  **DATE:**|Thursday, March 17, 2016 |
 +^  **TIME:**|1:15pm to 2:15pm |
 +^  **LOCATION:**|WH 100E |
 +^  **SPEAKER:**|Junyi Dong, Binghamton University |
 +^  **TITLE:**|Diagnostic Plotting Methods for Proportional Hazards Models  With Time-dependent Covariates or Time-varying Regression Coefficients|
 +
 +</WRAP>
 +\\ 
 +
 +<WRAP center box 80%>
 +<WRAP centeralign>**Abstract**</WRAP>Given a sample of regression data from $(Y,Z)$,
 +we propose several new diagnostic plotting methods for the Cox models
 +with the general external time-dependent covariates $Z$,
 +which can be continuous, or  with the
 +time-varying regression coefficients.
 +The main approach compares the non-parametric
 +MLE of the survival function  of $Y$
 +against its expected (correct) expression under the
 +given Cox model which can be mis-specified.
 +This is different from the existing methods in the literatures such as
 +log-log plots and residuals plots.
 +The simulation studies and the data analysis of our breast cancer
 +data suggest that the combination of these
 +diagnostic plotting methods we proposed performs quite satisfactorily.
 +These new diagnostic plotting methods naturally yield various
 +tests for checking the validity of the Cox models.
 +The main advantage of the new tests over the residual tests is
 +in the case that the data do not fit any PH model.
 +Then the new tests are still valid but not the residual tests. 
 +</WRAP>