This usually means there is something odd with the data or the model you
specified, or both. What does your design matrix looks like?
With a mixed design, the simplest would be to specify one-sample or
two-sample t-tests for each question you have (main effects, interaction).
On 22/04/17 12:16, Angelique Van Ombergen wrote:
> Hi all,
> I’m running a 2X2 ANOVA in SPM (with one within-group factor (pre and
> post scan) and one between-group factor (experimental and control group)
> and n=8 in each group).
> However, when running the model estimation, I get the following error:
> Chunk 1/1 : ...processing
> Failed 'Model estimation'
> Error using spm_est_non_sphericity (line 207)
> Please check your data: There are no significant voxels.
> In file "/Users/angeliquevanombergen/spm12/spm_est_non_sphericity.m"
> (v6827), function "spm_est_non_sphericity" at line 207.
> In file "/Users/angeliquevanombergen/spm12/spm_spm.m" (v6842), function
> "spm_spm" at line 431.
> In file "/Users/angeliquevanombergen/spm12/config/spm_run_fmri_est.m"
> (v5809), function "spm_run_fmri_est" at line 33.
> The following modules did not run:
> Failed: Model estimation
> I am just wondering whether this is an actual error or just the fact
> that there’s nothing significant (as it basically says). However, I’ve
> never had this error before, so I’m not sure.
> When I run a paired t-test between pre and post for each group
> separately, I do find significant differences though.
> Thanks for the advice!
> Best wishes,
> drs. Angelique Van Ombergen
> *Antwerp University Research centre for Equilibrium and Aerospace (AUREA) *
> *FWO research fellow*
> *University of Antwerp*
> Antwerp University Hospital (UZA)
> Wilrijkstraat 10 (route 71, B904)
> 2650 Edegem (Antwerp)
> lab phone: +32 (0)3 821 33 07
> mobile phone: +32 (0)4 73 237 820
> web: www.uantwerpen.be/aurea
> <http://www.uantwerpen.be/aurea> or www.uantwerpen.be/angelique-vanombergen
> blog: www.neuropolisblog.com <http://www.neuropolisblog.com/>
Guillaume Flandin, PhD
Wellcome Trust Centre for Neuroimaging
University College London
12 Queen Square
London WC1N 3BG