Editing Curve fitting (section)

===Fitting other functions to data points===
Other types of curves, such as [[trigonometric functions]] (such as sine and cosine), may also be used, in certain cases.

In spectroscopy, data may be fitted with [[Normal distribution|Gaussian]], [[Cauchy distribution|Lorentzian]], [[Voigt function|Voigt]] and related functions.

In biology, ecology, demography, epidemiology, and many other disciplines, the [[Population growth|growth of a population]], the spread of infectious disease, etc. can be fitted using the [[logistic function]].

In [[agriculture]] the inverted logistic [[sigmoid function]] (S-curve) is used to describe the relation between crop yield and growth factors. The blue figure was made by a sigmoid regression of data measured in farm lands. It can be seen that initially, i.e. at low soil salinity, the crop yield reduces slowly at increasing soil salinity, while thereafter the decrease progresses faster.