RE: [NMusers] VPC with Mixture Model

2009-04-15 Thread Mats Karlsson
rs@globomaxnm.com Subject: Re: [NMusers] VPC with Mixture Model Hi, I realized after I sent the comment below about mixture model **simulations** that Mats was no doubt referring to the problem of separating the two sub-populations in the **observed** data using MIXEST. This will of course be p

Re: [NMusers] VPC with Mixture Model

2009-04-14 Thread Nick Holford
Sweden phone: +46 18 4714105 fax: +46 18 471 4003 -Original Message- From: Leonid Gibiansky [mailto:lgibian...@quantpharm.com] Sent: Tuesday, April 14, 2009 9:06 PM To: Mats Karlsson Cc: 'Satyendra Suryawanshi'; nmusers@globomaxnm.com Subject: Re: [NMusers] VPC with Mixture Mod

RE: [NMusers] VPC with Mixture Model

2009-04-14 Thread Mats Karlsson
sala Sweden > phone: +46 18 4714105 > fax: +46 18 471 4003 > > > -Original Message- > From: Leonid Gibiansky [mailto:lgibian...@quantpharm.com] > Sent: Tuesday, April 14, 2009 9:06 PM > To: Mats Karlsson > Cc: 'Satyendra Suryawanshi'; nmusers@globomaxnm.c

Re: [NMusers] VPC with Mixture Model

2009-04-14 Thread Nick Holford
.com] Sent: Tuesday, April 14, 2009 9:06 PM To: Mats Karlsson Cc: 'Satyendra Suryawanshi'; nmusers@globomaxnm.com Subject: Re: [NMusers] VPC with Mixture Model Hi Mats, Could you elaborate why you would not stratify based on the subpopulations? It seems perfectly reasonable for

RE: [NMusers] VPC with Mixture Model

2009-04-14 Thread Mats Karlsson
om: Leonid Gibiansky [mailto:lgibian...@quantpharm.com] Sent: Tuesday, April 14, 2009 9:06 PM To: Mats Karlsson Cc: 'Satyendra Suryawanshi'; nmusers@globomaxnm.com Subject: Re: [NMusers] VPC with Mixture Model Hi Mats, Could you elaborate why you would not stratify based on the subp

Re: [NMusers] VPC with Mixture Model

2009-04-14 Thread Leonid Gibiansky
Hi Mats, Could you elaborate why you would not stratify based on the subpopulations? It seems perfectly reasonable for me to simulate from the model (including random assignment of subpopulations), and then compare "apples to apples": observed subpopulation versus simulated subpopulations. In

RE: [NMusers] VPC with Mixture Model

2009-04-14 Thread Mats Karlsson
Dear Satyendra, Interesting question. I don't think there is much written about this, but I may be wrong. What I would not do is to try to stratify based on estimated subpopulation allocation ("EST"). Rather I would use the same VPCs as if there had been no mixture model. Possibly what you coul