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help > RE: Sessions with different durations
Aug 14, 2017 04:08 PM | Ella Gabitov
RE: Sessions with different durations
Dear Alfonso,
Thank you very much for your fast and comprehensive reply.
The idea to use a covariate with the number of data-points as control variable in the 2nd-level analyses sounds like a good solution to control for inter-subjects differences. Do you think that introducing a covariate with differences in length / the number of time-points between sessions as 2nd-level covariate could also be a good control for differences in duration between sessions? Or, maybe, given that between-sessions comparison is performed on a subject-level, would it be better to control for these differences by using a 1st-level covariate? In the later case, I believe that for each session I could generate a vector with session duration for each time-point within this session and zeros otherwise. I would be glad to know what do you think about this approach. Do you think that there is a need to scale or to mean-center the covariates in any of the above-mentioned cases?
Thank you very much for your time,
Ella
Thank you very much for your fast and comprehensive reply.
The idea to use a covariate with the number of data-points as control variable in the 2nd-level analyses sounds like a good solution to control for inter-subjects differences. Do you think that introducing a covariate with differences in length / the number of time-points between sessions as 2nd-level covariate could also be a good control for differences in duration between sessions? Or, maybe, given that between-sessions comparison is performed on a subject-level, would it be better to control for these differences by using a 1st-level covariate? In the later case, I believe that for each session I could generate a vector with session duration for each time-point within this session and zeros otherwise. I would be glad to know what do you think about this approach. Do you think that there is a need to scale or to mean-center the covariates in any of the above-mentioned cases?
Thank you very much for your time,
Ella
Threaded View
Title | Author | Date |
---|---|---|
Ella Gabitov | Aug 11, 2017 | |
Alfonso Nieto-Castanon | Aug 12, 2017 | |
Ella Gabitov | Aug 14, 2017 | |