How do I perform unbalanced ANOVA ?

Hi! I have 3 vectors of data (each vector has a different number of data) and I'd like to perform ANOVA. How do I do it?

Answer 1

[Hanling Su]

Hey you can use anova1 but assign specific group variable, for example, you can create two vector, the first one is the observations of your sample, group by group data = [x11, x12, ... x120, x21, x22, ... x227, x31, x32, .. , x317]. And you create a correspongding group vector, for this example group = [1,1,1...,1, 2, 2, ... , 3, 3, ...], as long as the observations have the same index as its group, you can use anova1(data, group), it will automatically group the data for you.

Answer 2

[the cyclist]

If you have the Statistics Toolbox, you can use the anovan function to do unbalanced ANOVA.

Answer 3

[Samar Ragab]

try this ,

g1=ones(1,size(classA3,1));
g2=2*ones(1,size(classB3,1));
g3=3*ones(1,size(classC3,1));
p1=zeros(1,26);
for i=1:26   %%%crossponding to features numbers(columns)
x=[classA3(:,i);classB3(:,i);classC3(:,i)]' ;
g=[g1,g2,g3]; 
p1(i)=anova1(x,g,'off'); 
end