f = 

     General model:
     f(x) = a+b*(1./(1+exp(-d*(x-c))))
     Coefficients (with 95% confidence bounds):
       a =      -24.24  (-25.35, -23.14)
       b =      -1.798  (-5.363, 1.766)
       c =      -3.092  (-3.393, -2.792)
       d =      -24.58  (-152.5, 103.3)

fgof = 

  struct with fields:

           sse: 507.8828
       rsquare: 0.0436
           dfe: 54
    adjrsquare: -0.0095
          rmse: 3.0668


fout = 

  struct with fields:

           numobs: 58
         numparam: 4
        residuals: [58×1 double]
         Jacobian: [58×4 double]
         exitflag: 0
    firstorderopt: 3.8402
       iterations: 120
        funcCount: 605
     cgiterations: 0
        algorithm: 'trust-region-reflective'
         stepsize: 0.0019
          message: 'Fitting stopped because the number of iterations or function evaluations exceeded the specified maximum.'

