f = 

     General model:
     f(x) = a+b*(1./(1+exp(-d*(x-c))))
     Coefficients (with 95% confidence bounds):
       a =       2.006  (0.1219, 3.89)
       b =       2.483  (-0.1606, 5.126)
       c =      -3.177  (-4.603, -1.75)
       d =      0.6821  (-0.04793, 1.412)

fgof = 

  struct with fields:

           sse: 58.6138
       rsquare: 0.6648
           dfe: 1029
    adjrsquare: 0.6638
          rmse: 0.2387


fout = 

  struct with fields:

           numobs: 1033
         numparam: 4
        residuals: [1033×1 double]
         Jacobian: [1033×4 double]
         exitflag: 3
    firstorderopt: 0.1503
       iterations: 15
        funcCount: 80
     cgiterations: 0
        algorithm: 'trust-region-reflective'
         stepsize: 0.0083
          message: 'Success, but fitting stopped because change in residuals less than tolerance (TolFun).'
