Date: Jan 23, 2013 3:34 PM
Author: Derek Goring
Subject: Re: Single Trendline for multiple datasets

On Thursday, January 24, 2013 9:24:08 AM UTC+13, Charlotte  wrote:
> I have a plot with multiple datasets plotted, and would like to plot on top a single trendline for all the datasets - is there an easy way to do this?

1. Assemble all the data into two vectors, x and y
x=[x1(:);x2(:); etc ];
2. Fit a line to the data using least squares:
coef=[x ones(length(x),1)]\y;
3. Define the line:
xfit=[min(x) max(x)];
yfit=coef(1)*xfit + coef(2);
4. Plot
plot(x,y,'bo',xfit,yfit,'r-')