Note that this reference documentation is identical to the help that is displayed in MATLAB when you type “help ft_freqstatistics”.

  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