The data points shown here represent the length of day, from sunrise to sunset, at Boston, Massachusetts for the years 1995-1997. Daytime has been rounded off to the nearest minute. The abscissa is the day number [1/1/1995 = day 1].
Obviously, this simplified model is a very good fit.
Model
y = A sin ((2 π) B x + C) + D
Parameters
- A -- amplitude
- B -- frequency
- C -- phase shift
- D -- baseline