Hi all, I am trying to use FindFit in order to choose p and q parameters of ft function (which is actually a 4-parameter beta distribution) to match "data". I do not know why I get the Jacobean not being real warning at all times and also very poor fits. (If I do not specify starting guesses I get p->1 and q->1). Even if I specify starting values for p and q, FindFit just returns those very values. Can you please help me to have this curve fitting work properly? Maybe I am doing something wrong. The code is attached. Thanks a lot. Anna.