# Differences

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 — reference:ft_statfun_diff_itc [2018/08/23 14:43] (current) Line 1: Line 1: + =====  FT_STATFUN_DIFF_ITC ===== + + Note that this reference documentation is identical to the help that is displayed in MATLAB when you type "help ft_statfun_diff_itc"​. + + <​html><​pre>​ + <​font color=green>​FT_STATFUN_DIFF_ITC​ computes the difference in the inter-trial coherence between + two conditions. The input data for this test should consist of complex-values + spectral estimates, e.g. computed using <​font color=green>​FT_FREQANALYSIS​ with method=mtmfft,​ wavelet + or mtmconvcol. + + The ITC is a measure of phase consistency over trials. By randomlly shuffling the + trials ​ between the two consitions and repeatedly computing the ITC difference, you + can test the significance of the two conditions having a different ITC. + + A difference in the number of trials poer condition will affect the ITC, however + since the number of trials remains the same for each random permutation,​ this bias + is reflected in the randomization distribution. + + Use this function by calling the high-level statistic functions as + [stat] = ft_freqstatistics(cfg,​ freq1, freq2, ...) + with the following configuration options + cfg.method ​   = '​montecarlo'​ + cfg.statistic = '​diff_itc'​ + and optionally the options + ​cfg.complex ​   = '​diffabs'​ to compute the difference of the absolute ITC values (default), or + '​absdiff'​ to compute the absolute value of the difference in the complex ITC values. + ​ + For this specific statistic there is no known parametric distribution,​ hence the + probability and critical value cannot be computed. This specific statistic can + therefore only be used with cfg.method='​montecarlo'​. If you want to do this in + combination with cfg.correctm='​cluster',​ you also need either + cfg.clusterthreshold='​nonparametric_common'​ or '​nonparametric_individual'​. + + See <​font color=green>​FT_FREQSTATISTICS​ and <​font color=green>​FT_STATISTICS_MONTECARLO​ for more details +