Why do we have these different line fits and which is true ?
The important thing to consider in such curve fits is the value of R2, sometime denoted as r2. A value of 1 means a perfect fit and a value of zero means absolutely not fit.
All four curved lines have a fit greater or equal to 0.902. That is a good result.
The Gompertz fit has an R2 of 0.917 which is the highest value of the options presented. It means that for the data analyzed and evaluated in this study the Gompertz fit is the one that best describes the data. However, given the closeness of R2 values, the other options also give good results, but not as good as the Gompertz fit.