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diff --git a/modules/statistics/macros/ftuneq.sci b/modules/statistics/macros/ftuneq.sci new file mode 100755 index 000000000..166a79621 --- /dev/null +++ b/modules/statistics/macros/ftuneq.sci @@ -0,0 +1,59 @@ + +// Scilab ( http://www.scilab.org/ ) - This file is part of Scilab +// Copyright (C) 2012 - Michael Baudin +// Copyright (C) 2000 - INRIA - Carlos Klimann +// +// This file must be used under the terms of the CeCILL. +// This source file is licensed as described in the file COPYING, which +// you should have received as part of this distribution. The terms +// are also available at +// http://www.cecill.info/licences/Licence_CeCILL_V2.1-en.txt +// + +function [f,p]=ftuneq(varargin) + // + //This function computes the F ratio for samples of unequal + //size. + // + //"The most efficient design is to make all samples the + //same size n. However when this is nor feasible, it + //still is possible to modify the ANOVA calculations." + //Note that the definition of xbarbar is no longer + //mean(xbar), but rather a weighted average with weights + //ni. Additionally it gives (in p) the p-value of the + //computed Fischer ratio. + // + //Given a number a of samples each of them composed of n_i + //(i from 1 to a) observations this fonction computes in f + //the Fischer ratio (it is the ratio between nr times the + //variance of the means of samples and the mean of the + //variances of each sample). + // + //References: Wonacott, T.H. & Wonacott, R.J.; Introductory + //Statistics, J.Wiley & Sons, 1990. + // + // + [lhs,rhs]=argn(0) + if rhs == 0 then + error(msprintf(gettext("%s: Wrong number of input arguments: At least %d expected.\n"),"ftuneq",1)) + end + data=[] + total=0 + sse=0 + for i=1:rhs + len(i)=size(varargin(i),"*"), + mat=matrix(varargin(i),len(i),1), + partial=sum(mat), + xbar(i)=partial/len(i), + total=total+partial, + data=[data; mat] + sse=sse+sum((mat-xbar(i)).^2) + end + xbarbar=total/sum(len) + ssa=len'*((xbar-xbarbar).^2) + msa=ssa/(rhs-1) + deglib=sum(len-1) + mse=sse/deglib + f=msa/mse + [ignored,p]=cdff("PQ",f,(rhs-1),deglib) +endfunction |