Additional Information
Model: y = f(x;beta) + e = beta(1)exp[-beta(2)x] + beta(3)exp[-beta(4)x] + beta(5)exp[-beta(6)x] + e
These data are taken from an example discussed in Lanczos (1956). The data were generated to 6-digits of accuracy using f(x) = 0.0951*exp(-x) + 0.8607*exp(-3*x) + 1.5576*exp(-5*x).