In the early hours of this morning, when I was having difficulty sleeping, I decided to have a go a seeing if I could do this (nothing on TV!) A few Google searches later and I found some good links of polynomial equation calculation and Microsoft Excel.
So this is my first attempt at working out polynomial equations, in orders from linear to 4th order – I am very proud! (Although please let me know if it is a load of rubbish!!)
Andy
Download Polynomial Calculator Spreadsheet:
Calculation spreadsheet for higher order polynomials Excel Andrew Thornett 100818
Screenshot of 3rd order polynomial calculation version of above spreadsheet, compared to Dr Elliott’s linear calulation spreadsheet for same data:
There are other trendline functions in Microsoft Excel as well as polynomials that might be a better fit. I don’t like high order polynomials as they tend to go berserk outside your data range. Mind you, your data looks benign enough for it not to be a problem. Looks pretty nearly linear anyway.
Roger
The spectrum analysis software, as far as I know, only accepts polynomials rather than other trendline functions.
Andy