function pval = circ_symtest(alpha) % % [pval, z] = circ_symtest(alpha,w) % Tests for symmetry about the median. % H0: the population is symmetrical around the median % HA: the population is not symmetrical around the median % % Input: % alpha sample of angles in radians % % Output: % pval p-value % % PHB 3/19/2009 % % References: % Biostatistical Analysis, J. H. Zar, 27.4 % % Circular Statistics Toolbox for Matlab % By Philipp Berens, 2009 % berens@tuebingen.mpg.de - www.kyb.mpg.de/~berens/circStat.html if size(alpha,2) > size(alpha,1) alpha = alpha'; end % compute median md = circ_median(alpha); % compute deviations from median d = circ_dist(alpha,md); % compute wilcoxon sign rank test pval = signrank(d);