Hi all,
I am trying to fit a sigmoidal curve in a chart. I have days of year (3 years) and hours of light (from 10 the minimum to 16 de maximum) by changing 30 minutes of light every week. Does anyone know how to representate a smooth (or trendline) on the graph. The polynomial trendline only goes up to 6th order and it only works for a single year. thanks