Reply-To: | | [log in to unmask][log in to unmask] >> To: [log in to unmask] >> CC: [log in to unmask] > >> >> The null hypothesis is defined before you create the contrasts. The >> contrasts are based on your null hypothesis. >> >> You should not be testing group differences in a 1st level model; >> rather, you should take estimates of the first level model from each >> subject to the second level random effects model. >> >> Best Regards, Donald McLaren >> ================= >> D.G. McLaren, Ph.D. >> Research Fellow, Department of Neurology, Massachusetts General Hospital >> and >> Harvard Medical School >> Postdoctoral Research Fellow, GRECC, Bedford VA >> Website: http://www.martinos.org/~mclaren >> Office: (773) 406-2464 >> ===================== >> This e-mail contains CONFIDENTIAL INFORMATION which may contain PROTECTED >> HEALTHCARE INFORMATION and may also be LEGALLY PRIVILEGED and which is >> intended only for the use of the individual or entity named above. If the >> reader of the e-mail is not the intended recipient or the employee or >> agent >> responsible for delivering it to the intended recipient, you are hereby >> notified that you are in possession of confidential and privileged >> information. Any unauthorized use, disclosure, copying or the taking of >> any >> action in reliance on the contents of this information is strictly >> prohibited and may be unlawful. If you have received this e-mail >> unintentionally, please immediately notify the sender via telephone at >> (773) >> 406-2464 or email. >> >> >> On Wed, Dec 5, 2012 at 9:02 AM, Qasim Bukhari <[log in to unmask]> >> wrote: >> > Dear SPM Expert, >> > I m trying to run an analysis differentiating between the two >> > population. I >> > have two groups, group 1 and group 2. These two group differ under one >> > of >> > the regressor; which is an extracted time series of region R1. I tried >> > to >> > run 3 different experiments >> > >> > Experiment 1: group 1 vs group 1 : fixed effect analysis >> > I input two different subjects but both from group 1. Under the multiple >> > regressors; I input the extracted time series of region R1. In order to >> > see >> > the results; I defined an F-contrast, with (1,1) imagining that its the >> > same >> > group so the contrast should also be the same. However in the result; I >> > see >> > quite a lot activations. I wasnt expecting that, since these are from >> > the >> > same population >> > >> > Experiment 2: group 2 vs group 2 : fixed effect analysis >> > I did the same procedure as described above however this time for group >> > 2. >> > The results were same as mentioned above; while I was expecting >> > contrary. >> > >> > Experiment 3: group 1 vs group 2 : fixed effect analysis >> > This time, I input different subjects from the different groups; however >> > I >> > keKh |