FT_FREQSTATISTICS computes significance probabilities and/or critical
values of a parametric statistical test or a non-parametric permutation
test.
Use as
[stat] = ft_freqstatistics(cfg, freq1, freq2, ...)
where the input data is the result from FT_FREQANALYSIS, FT_FREQDESCRIPTIVES
or from FT_FREQGRANDAVERAGE.
The configuration can contain the following options for data selection
cfg.channel = Nx1 cell-array with selection of channels (default = 'all'),
see FT_CHANNELSELECTION for details
cfg.latency = [begin end] in seconds or 'all' (default = 'all')
cfg.frequency = [begin end], can be 'all' (default = 'all')
cfg.avgoverchan = 'yes' or 'no' (default = 'no')
cfg.avgovertime = 'yes' or 'no' (default = 'no')
cfg.avgoverfreq = 'yes' or 'no' (default = 'no')
cfg.parameter = string (default = 'powspctrm')
If you specify cfg.correctm='cluster', then the following is required
cfg.neighbours = neighbourhood structure, see FT_PREPARE_NEIGHBOURS
Furthermore, the configuration should contain
cfg.method = different methods for calculating the significance probability and/or critical value
'montecarlo' get Monte-Carlo estimates of the significance probabilities and/or critical values from the permutation distribution,
'analytic' get significance probabilities and/or critical values from the analytic reference distribution (typically, the sampling distribution under the null hypothesis),
'stats' use a parametric test from the MATLAB statistics toolbox,
'crossvalidate' use crossvalidation to compute predictive performance
cfg.design = Nxnumobservations: design matrix (for examples/advice, please see the Fieldtrip wiki,
especially cluster-permutation tutorial and the 'walkthrough' design-matrix section)
The other cfg options depend on the method that you select. You
should read the help of the respective subfunction FT_STATISTICS_XXX
for the corresponding configuration options and for a detailed
explanation of each method.
To facilitate data-handling and distributed computing you can use
cfg.inputfile = ...
cfg.outputfile = ...
If you specify one of these (or both) the input data will be read from a *.mat
file on disk and/or the output data will be written to a *.mat file. These mat
files should contain only a single variable, corresponding with the
input/output structure.
See also FT_FREQANALYSIS, FT_FREQDESCRIPTIVES, FT_FREQGRANDAVERAGE