f = 

     General model:
     f(x) = a+b*(1./(1+exp(-d*(x-c))))
     Coefficients (with 95% confidence bounds):
       a =      -9.394  (-11.62, -7.164)
       b =       8.162  (5.796, 10.53)
       c =      -2.853  (-2.958, -2.748)
       d =       8.782  (4.054, 13.51)

fgof = 

  struct with fields:

           sse: 218.4474
       rsquare: 0.6515
           dfe: 82
    adjrsquare: 0.6387
          rmse: 1.6322


fout = 

  struct with fields:

           numobs: 86
         numparam: 4
        residuals: [86×1 double]
         Jacobian: [86×4 double]
         exitflag: 3
    firstorderopt: 0.1005
       iterations: 14
        funcCount: 75
     cgiterations: 0
        algorithm: 'trust-region-reflective'
         stepsize: 0.0068
          message: 'Success, but fitting stopped because change in residuals less than tolerance (TolFun).'
