I understand that I can run stats (e.g. one sample t-test) and thus get significance results (p-values) on second-level models. However, I don't see how to do the same at the first level (within-subject). If I undferstand correctly the only info I can get at the first level are parameter estimates and peak of estimated response.
Thanks and best,
Ambra
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PsPM offers no first-level statistical tests. The reason is that the data are strongly auto-correlated, and models to account for that (as e.g. in SPM for fMRI) can be quite complicated, or unreliable with just one data channel.
As a surrogate, you can safely assume that trial-by-trial statistics are independent, and do statistical tests on this level after extracting them to e.g. in R or SPSS.
Dominik
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You can run a GLM with one regressor per trial rather than per condition (ie. define 'conditions' that just contain one trial). In DCM you automatically get trial-by-trial estimates.
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Hello,
I understand that I can run stats (e.g. one sample t-test) and thus get significance results (p-values) on second-level models. However, I don't see how to do the same at the first level (within-subject). If I undferstand correctly the only info I can get at the first level are parameter estimates and peak of estimated response.
Thanks and best,
Ambra
Hi Ambra
PsPM offers no first-level statistical tests. The reason is that the data are strongly auto-correlated, and models to account for that (as e.g. in SPM for fMRI) can be quite complicated, or unreliable with just one data channel.
As a surrogate, you can safely assume that trial-by-trial statistics are independent, and do statistical tests on this level after extracting them to e.g. in R or SPSS.
Dominik
Hello Dominik,
thanks for your reply.
How would you create trial-by-trial statistics?
Thanks and best,
Ambra
You can run a GLM with one regressor per trial rather than per condition (ie. define 'conditions' that just contain one trial). In DCM you automatically get trial-by-trial estimates.