ttest - 2 matrices

Hello, I have 2 matrices 52x21x49. Here x=52, y=21 and each of these 'tiles' have 49 values.

 I want to do a ttest on each tile to see if the 49 values in each tile of matrix A is drawn from a different distribution than the same tile in matrix B.

Therefore my h and p should = 52x21 each. Is there a smart way of doing this without a for loop?

Thanks, S

Answer 1

[Tom Lane]

Since TTEST wants to work along the first dimension, you can just move that dimension to the front using PERMUTE. Then use SQUEEZE to get rid of the extra dimension. Something like this:

>> a = rand(3,4,5);
>> b = rand(3,4,5);
>> [h,p] = ttest2(permute(a,[3 1 2]),permute(b,[3 1 2]));
>> squeeze(h)
ans =
     0     0     0     0
     0     0     0     0
     0     0     1     0
>> squeeze(p)
ans =
    0.6347    0.2035    0.2729    0.6062
    0.7198    0.7766    0.0945    0.5118
    0.2029    0.5078    0.0111    0.3311

[sas0701]

Perfect! Thank you:)

[Henry Fu]

Another way to do this is to specify dimension in ttest.

e.g. [h,p] = ttest(a,b,'Dim',3);