MATLAB: F-test for the equality of means

ftest

Hi, how can i test for equality of means for >2 vectors?, Thanks in advance

Best Answer

You can use anova1() to compare the means of two or more groups.

That function returns the F statistic in the optional anovatab argument.

strength = [82 86 79 83 84 85 86 87 74 82 ...
            78 75 76 77 79 79 77 78 82 79];
alloy = {'st','st','st','st','st','st','st','st',...
         'al1','al1','al1','al1','al1','al1',...
         'al2','al2','al2','al2','al2','al2'};
[p,anovatab,stats] = anova1(strength,alloy);

Related Solutions

MATLAB: Anova1 within groups degree of freedom

 strength = [82 86 79 83 84 85 86 87 74 82  78 75 76 77 79 79 77 78 82 79];
  alloy = {'st','st','st','st','st','st','st','st','al1','al1','al1','al1','al1','al1', 'al2','al2','al2','al2','al2','al2'};
 p = anova1(strength,alloy)

If N is the total number of observations and k is the number of groups, then N-k is the within groups DOF, k-1 is the between, and N-1 is the total. N-1 = (N-k) + (k-1). On the anova1 table these are:

k -1 (Groups)

N-k (Error)

N-1 (Total)

     withingroup = length(strength) - length(unique(alloy))
     betweengroup = length(unique(alloy))-1
     totaldof = length(strength)-1

In the above, you can see that the F statistic value should be:

   Fval = (184.8/2)/(102/17)

MATLAB: How to decrease the number of points in a matrix

I suggest http://www.mathworks.com/help/matlab/ref/spline.html

x = 1 : length(psdn);
x128 = linspace(x(1), x(end), 128);
p128 = spline(x, psdn, x128);
plot(x128, p128);

Best Answer

Related Solutions

MATLAB: Anova1 within groups degree of freedom

MATLAB: How to decrease the number of points in a matrix

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