f = 

     General model:
    f(x) = a+b*(1./(1+exp(-d*(x-c))))
     Coefficients (with 95% confidence bounds):
       a =       2.957  (2.931, 2.984)
       b =       1.344  (1.272, 1.415)
       c =      -2.191  (-2.278, -2.104)
       d =       1.409  (1.25, 1.568)

fgof = 

  struct with fields:

           sse: 142.6935
       rsquare: 0.7684
           dfe: 2076
    adjrsquare: 0.7681
          rmse: 0.2622


fout = 

  struct with fields:

           numobs: 2080
         numparam: 4
        residuals: [2080×1 double]
         Jacobian: [2080×4 double]
         exitflag: 3
    firstorderopt: 0.0155
       iterations: 7
        funcCount: 40
     cgiterations: 0
        algorithm: 'trust-region-reflective'
         stepsize: 7.8856e-04
          message: 'Success, but fitting stopped because change in residuals less than tolerance (TolFun).'
