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Thank you! Heidi ================================================ Dr. Heidi Jacobs Postdoc researcher Faculty of Health, Medicine and Life Sciences School for Mental Health and Neurosciences Division Cognitive Neuropsychiatry and Clinical Neurosciences Alzheimer Center Limburg [log in to unmask] www.maastrichtuniversity.nl www.heidijacobs.nl Dr. Tanslaan 12, 6229 ET Maastricht P.O. Box 616, 6200 MD Maastricht, The Netherlands T +31 43 38 84 090 F +31 43 38 84 092 ================================================ ________________________________________ Van: FSL - FMRIB's Software Library [[log in to unmask]] namens Anders Eklund [[log in to unmask]] Verzonden: donderdag 2 mei 2013 19:19 Aan: [log in to unmask] Onderwerp: [FSL] SV: [FSL] power / sample size question See http://fmripower.org/ http://www.stat.ubc.ca/~rollin/stats/ssize/ -Anders ________________________________________ Från: FSL - FMRIB's Software Library [[log in to unmask]] för Jacobs H (NP) [[log in to unmask]] Skickat: den 2 maj 2013 13:00 Till: [log in to unmask] Ämne: Re: [FSL] power / sample size question Hi, I know, but I don't know how to get that value from published studies? This is a review of a grant proposal, so I have not yet done this study. Is there a way to simulate this and calculate the required sample sizes? Thanks Heidi ________________________________________ Van: FSL - FMRIB's Software Library [[log in to unmask]] namens Stephen Smith [[log in to unmask]] Verzonden: donderdag 2 mei 2013 17:50 Aan: [log in to unmask] Onderwerp: Re: [FSL] power / sample size question It depends on the effect size. Steve. On 2 May 2013, at 16:41, "Jacobs H (NP)" <[log in to unmask]<mailto:[log in to unmask]>> wrote: Hi all, For my fMRI study I have 30 individuals per group (two groups). Both groups were randomized to placebo or treatment condition (so 15 individuals per condition). I compared both groups (irrespective of condition) at baseline and also investigated the treatment effect (follow-up) Would this be a sufficient sample size? I have a reviewer who is wondering this.... Any suggestions or tips are welcome! Thanks! Heidi ================================================ Dr. Heidi Jacobs Postdoc researcher Faculty of Health, Medicine and Life Sciences School for Mental Health and Neurosciences Division Cognitive Neuropsychiatry and Clinical Neurosciences Alzheimer Center Limburg [log in to unmask]<mailto:[log in to unmask]> www.maastrichtuniversity.nl www.heidijacobs.nl Dr. Tanslaan 12, 6229 ET Maastricht P.O. Box 616, 6200 MD Maastricht, The Netherlands T +31 43 38 84 090 F +31 43 38 84 092 ================================================ --------------------------------------------------------------------------- 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) 2176 [log in to unmask]<mailto:[log in to unmask]> http://www.fmrib.ox.ac.uk/~steve ---------------------------------------------------------------------------