sorry, what I meant to request is that you keep everything in a single email. If they are spread out over multiple emails, then we have to go back and find the relevant ones. As you know, we answer many emails, and it is burdensome to have to keep track of particular emails. thanks! doug
On 11/27/2012 04:00 PM, MAHINDA YOGARAJAH wrote: > Hi Doug, > > Sorry the previous suggestion referred to a suggestion from Donald > earlier in the thread as follows: > > "You might consider the contrast > [0 1.5 .5 -.5 -1.5] across all 5 groups showing a linear effect of > disease severity. The first column being controls." > I will try that suggestion out, but I have also grouped all the patients and > controls together in 1 group (as opposed to 5 different groups), and given > that controls contains no endogenous factor giving them a covariate of 1, and > then P1 a value of 2, P2 a value of 3, P3 a values of 4 and P4 a value of 5. > There are good biological grounds to suspect that that the endogenous factor > will increase linearly from P1 to P5, though the values 1 to 5 I have chosen > are arbitrary. > When I then run the GLM looking for correlation between dependent measure and > this covariate, I see significant results in a similar (though more > widespread) location compared to when I simply look for a difference between > all controls and all patients (C v combined P1 to P4). Thus, I think (hope) > the model has shown that > Hopefully this is one valid way in which to show that it is the > changes in the level of the endogenous factor contribute to the > overall group differences (C v combined P1 to P4). Do you agree ? > > I will however try Donald's method as I also want to show that the > interaction between age-thickness (that I see in C v combined P1 to > P4) shows a linear effect across P1 to P4. Any suggestions for how I > do that ? > > Thanks, > > M -- Douglas N. Greve, Ph.D. MGH-NMR Center gr...@nmr.mgh.harvard.edu Phone Number: 617-724-2358 Fax: 617-726-7422 Bugs: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting FileDrop: www.nmr.mgh.harvard.edu/facility/filedrop/index.html Outgoing: ftp://surfer.nmr.mgh.harvard.edu/transfer/outgoing/flat/greve/ _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer The information in this e-mail is intended only for the person to whom it is addressed. If you believe this e-mail was sent to you in error and the e-mail contains patient information, please contact the Partners Compliance HelpLine at http://www.partners.org/complianceline . If the e-mail was sent to you in error but does not contain patient information, please contact the sender and properly dispose of the e-mail.
