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thank you very much for your answer! Best regards, Ali Am@d ________________________________ De : Stephen Smith <[log in to unmask]> À : [log in to unmask] Envoyé le : Samedi 11 février 2012 11h15 Objet : Re: [FSL] question about tbss results Hi - yes you really need to be using corrected p-values in order to be sure of significance. tstats of 0.01-0.02 are VERY small, if you really mean that - I would not expect those to reach significance. Also - An FA threshold of 0.1 seems rather low - this would normally mean that you are including a lot of quite variable more minor tracts, which will reduce the power of your stats. Cheers. On 10 Feb 2012, at 09:14, amad ali wrote: Dear FSL experts, > >I ran a tbss analysis between 12 vs 13 very selected patients (same disease but they only differ in clinical presentation). >My parameters were : FA threshold = 0.1, TFCE option and 10 000 permutations. >I've got very intersting results (corresponding exactly to our hypothesis) but only in the raw t-statistic image (tstat1 < 0.01 and tstat2 < 0.05). Unfortunately, I've got no results in the tbss_tfce_corrp files. >Do you think that my results are usable like that or that they are too open to criticism ? > >Thank you very much in advance for your answers and your comments ! > >Best regards, > >Ali Amad --------------------------------------------------------------------------- Stephen M. Smith, Professor of Biomedical Engineering Associate Director, Oxford University FMRIB Centre FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK +44 (0) 1865 222726 (fax 222717) [log in to unmask] http://www.fmrib.ox.ac.uk/~steve ---------------------------------------------------------------------------