>> stat = ft_freqstatistics(cfg, data_brain{:});
Warning: Multiple versions of eeglab on your path will confuse FieldTrip 
> In ft_warning at 181
  In ft_defaults>checkMultipleToolbox at 265
  In ft_defaults at 100
  In ft_freqstatistics at 73 
Warning: one version of eeglab is found here: C:\Program
Files\MATLAB\R2013a\toolbox\fieldtrip-20151111\external\eeglab\eeglab2fieldtrip.m 
> In ft_defaults>checkMultipleToolbox at 268
  In ft_defaults at 100
  In ft_freqstatistics at 73 
Warning: one version of eeglab is found here: C:\Program
Files\MATLAB\R2013a\toolbox\eeglab13_4_3b\plugins\dipfit2.3\eeglab2fieldtrip.m 
> In ft_defaults>checkMultipleToolbox at 268
  In ft_defaults at 100
  In ft_freqstatistics at 73 
Warning: You probably used addpath(genpath('path_to_fieldtrip')), this can lead to unexpected
behaviour. See
http://fieldtrip.fcdonders.nl/faq/should_i_add_fieldtrip_with_all_subdirectories_to_my_matlab_path 
> In ft_warning at 181
  In ft_defaults>checkMultipleToolbox at 271
  In ft_defaults at 100
  In ft_freqstatistics at 73 
the call to "ft_selectdata" took 1 seconds
using "ft_statistics_montecarlo" for the statistical testing
Warning: doing a two-sided test without correcting p-values or alpha-level, p-values and alpha-level
will reflect one-sided tests per tail 
> In ft_statistics_montecarlo at 190
  In ft_freqstatistics at 190 
using "ft_statfun_correlationT" for the single-sample statistics
constructing randomized design
total number of measurements     = 3
total number of variables        = 1
number of independent variables  = 1
number of unit variables         = 0
number of within-cell variables  = 0
number of control variables      = 0
using a permutation resampling approach
computing statistic
Error using ft_statfun_correlationT (line 81)
uvar must be specified for dependent samples statistics

Error in ft_statistics_montecarlo (line 276)
  [statobs, cfg] = statfun(cfg, dat, design);

Error in ft_freqstatistics (line 190)
    [stat, cfg] = statmethod(cfg, dat, design);