I'm using nlmefit, and am trying to test the hypotheses using linhyptest. For that I need the covariance of the parameter estimates. The documentation suggests that the "stats" output structure should have a field called "covb". My output structure does not contain this!
[beta,psi,stats,re_subj] = nlmefit( X , Y, ,
@(b,X)X*b', [0,0,0,0], 'REParam', );
sebeta: [0.4017 0.0919 0.0426 0.0426]
How can I get the required matrix? (I was expecting a 4x4, with 'sebeta.^2' as diagonals maybe?)