How do I approach fitting these data? I am attaching the modelled.m file which calls on cdf_cal.m function to estimate values for input data that correctly fit cumulative distribution function data (f) provided in the modelled.m file..

I have tried to improve the initial guess (b0) by changing it from 10 to 50 but seems impossible to fit all the data. I have been stuck with this fitting problem for days now. Please help!