Sky,
Yes, your assumption is correct. The colors are relative to the first variable in the description, as you have described.
As a side note, the <factor>.levels file is not strictly necessary (thats the file that specifies your discrete factor names), since the loader will figure out discrete factors from continuous. But if you do create one, then it will use the order in that file. So if you swap the order in the file, your reds and blues should swap when you re-run the analysis. Its a good idea to have those .levels files anyway, as it is used to cross-check the qdec.table.dat file.
Nick
On Wed, 2008-06-11 at 10:48 -0700, Sky Raptentsetsang wrote:
Hello Surfers,
I just wanted to confirm what I am interpreting in some analysis in qdec. Some fellow techs here are running qdec on a group of controls, TBI and PTSD subjects and are trying to figure out what exactly the color scale is telling us. From the mail archive I understand that the blue represents a significant decrease and red is a increase. If the scalar description "Does the average thickness differ between TBI and PTSD" is chosen, I'm thinking the blue represents the area where TBI shows a significant decrease in avg. thickness from PTSD subjects, and the red would show a significant increase in avg. thickness in the TBI subjects compared to the PTSD. Basically, is the color scale bar in relation to the first variable in the scalar description (in this case TBI) or the second. Is this assumption correct?
Thanks,
Sky Raptentsetsang
Staff Research Associate CIND, San Francisco VAMC Department of Radiology, UCSF 4150 Clement St. Bldg. 13, 2nd Floor, Mail Stop 114M San Francisco, CA 94121 Phone 415.221.4810 ext. 4186 Fax 415.386.3954
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