Dear Ping Gong,
At 11:05 AM 6/28/2005 +0800, P.Gong wrote:
> >result is "P=0.001 with a corrected P of 0.05",
>
> >The "FWE" button thresholds voxels based on their corrected p-values, to
> be displayed in the glass brain later on, whereas the "none" button
> thresholds voxels based on their uncorrected p-values. Note that,
> p-values in both cases (corrected or uncorrected) I refer to voxel-level
> p-values.
>
> >Now, in the case of "p=0.001 with a corrected P of 0.05", it usually
> refers to corrected p-values for cluster extent, rather than voxel
> intensity. To perform such a cluster size test, you need to apply an
> uncorrected threshold (i.e., "none") to form clusters, then assess your
> activation
>based on corrected cluster-extent p-values. In your example, you first
>apply a threshold with "none" at 0.001 to form clusters, then look for
>clusters with p<0.05 corrected in terms of cluster extent.
>
>Do you mean in the case of "p=0.001 with a corrected P of 0.05", I select
>"none" button but not "FWE". And in option of "shreshold" I input 0.001.
>Last , find the corrected P value below cluster-level and p<0.05 ? Am I
>right or wrong?
Yes, you are right.
>
>Now, the result of "corrected P<0.01" Does it is the value of selecting
>"FWE" and inputing 0.01?
>If the resullt of "uncorrected P<0.01", does it is the value of selecting
>"none" and inputing 0.01?
You are right. If you are interested in "corrected p<0.01", then press
"FWE" and enter 0.01. Or if you are interested in "uncorrected p<0.01",
then press "none" and enter 0.01.
Good luck!
-Satoru
Satoru Hayasaka ==============================================
Post-Doctoral Fellow, MR Unit, UCSF / VA Medical Center
Email: shayasak_at_itsa_dot_ucsf_dot_edu Phone:(415) 221-4810 x4237
Homepage: http://www.umich.edu/~hayasaka
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