%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Compute inverse of the Chi square cumulative distribution function% % CALL % % x = Chi2inv(p,v);% % % INPUT% % - p, probability or significance level% - v, degrees of freedom of the distribution% % Example: If you want the 95% confidence interval for a chi2 variable you% should call% % x = utils.math.Chi2inv([0.05/2 1-0.05/2],v)% % References:% [1] M. Abramowitz and I. A. Stegun, "Handbook of Mathematical% Functions", Government Printing Office, 1964, 26.4.% %% L Ferraioli 14-02-2011%% $Id: Chi2inv.m,v 1.2 2011/05/30 17:18:09 luigi Exp $%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%function x = Chi2inv(p,v)a = v/2;b = 2;% Call the gamma inverse function. % x = gaminv(p,v/2,2); % uses statistic toolboxq = gammaincinv(p,a,'lower');x = q.*b;end