Re: [HCP-Users] How to threshold the task data?

[Harms, Michael]

Hi, The file has "zstat" in its name, so it is the z-statistic from the Level 3 group model across 440 related subjects ("R440").  You could compute a p-value from a standard normal distribution, but those p-values will not be fully accurate, because as we note in the data release manual, the model for computing the z-stats didn't account for the familial relationships between subjects (i.e., the R440 subjects are not an independent group of subjects).  You could use the "U100" set of subjects instead, which are 100 unrelated subjects.  In that case, p-values computed from the z-stat should be accurate, but note that those will be grayordinate-wise p-values, and will not be corrected for multiple comparisons. cheers, -MH --  Michael Harms, Ph.D. ----------------------------------------------------------- Conte Center for the Neuroscience of Mental Disorders Washington University School of Medicine Department of Psychiatry, Box 8134 660 South Euclid Ave. Tel: 314-747-6173 St. Louis, MO  63110 Email: mha...@wustl.edu From: Long <longspac...@gmail.com> Date: Wednesday, November 26, 2014 6:50 AM To: "hcp-users@humanconnectome.org" <hcp-users@humanconnectome.org> Subject: [HCP-Users] How to threshold the task data? Dear all, I tried to run statistical analysis on the task data, for instance, HCP_Q1-Q6_R440_tfMRI_ALLTASKS_level3_zstat1_hp200_s2.dscalar.nii. However I don't know if the data contained z score or beta score, and how to calculate the p value from the task data. Thank you in advance for helping! Best, Xiangyu _______________________________________________ HCP-Users mailing list HCP-Users@humanconnectome.org http://lists.humanconnectome.org/mailman/listinfo/hcp-users   The materials in this message are private and may contain Protected Healthcare Information or other information of a sensitive nature. If you are not the intended recipient, be advised that any unauthorized use, disclosure, copying or the taking of any action in reliance on the contents of this information is strictly prohibited. If you have received this email in error, please immediately notify the sender via telephone or return mail. _______________________________________________ HCP-Users mailing list HCP-Users@humanconnectome.org http://lists.humanconnectome.org/mailman/listinfo/hcp-users