Re: [R] testing parallelism of does-response curves using nls()

Hi John, you may have a look at the drc-package (or look at the maintainers web site www.bioassay.dk) I think it does exactly what you want. HTH Eik array chip schrieb: Hi, I am trying to use F test or Chi-square test to test if 2 5-parameter (A, B, xmid, scal and H) logistic curves are

[R] testing parallelism of does-response curves using nls()

Hi, I am trying to use F test or Chi-square test to test if 2 5-parameter (A, B, xmid, scal and H) logistic curves are parallel based on residual sum of squares. What's usually done is to first fit the 2 curves using a constraint (or global) model where all parameters are kept the same except