Creating a null distribution to find p-values of DVARS metric #13
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…s between voxels in timeseries
…ifferences in voxel timeseries
…ibution_mean function to calculate the median of voxel IQR timeseries differences instead of the mean (look at reference paper beneath equation 13)
…iance using power calculation and calculation of z-scores using the null distribution
merging changes added functions which calculate the null variance, correction to the null variance and z-scores (these still need to be tested!!) still to do: test functions calculate p-values bonferroni correction for p-values
…2 metrics are still too high so p-values calculated are all too small
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Hi @AnriiGegliuk and @oesteban
Here is some code which attempts to calculate the probability that each DVARS value comes from artefact free scans. The DVARS metric is assumed to follow a chi^2 distribution and the process of calculating parameters for the null distribution is found in this paper: https://www.sciencedirect.com/science/article/pii/S1053811917311229?via%3Dihub#appsecE
Unfortunately the final chi^2 metrics calculated are far too high for all DVARS in test scans (leading to all values being statistically significant) - I have tried to troubleshoot by using different methods to calculate the null distribution variance and null distribution mean, however this has not worked.
I'll keep working on it but any suggestions would be great!