How can I include an equation in a scatter plot with linear regression line?

Hi,

I'm trying to add the equation for a linear regression line to a scatter plot that I have made. I first plotted my data points then used the polyfit function to add a first-order line to my plot. Now I want the equation of the line in y = mx + b form to appear on my scatter plot, and I want the equation to update as I change my data points. Is there a command to help me do this?

Here's my code for adding the line:

%Find the best fit line for this data

bestfit = polyfit(Year,disp_pr_s,1);

disp_pr_s = bestfit(1)*Year + bestfit(2);

hold on

plot(Year,disp_pr_s,'k')

hold off

Thanks in advance!

Answer 1

[Image Analyst]

Use sprintf() to build a string. Then use text() to place it

theString = sprintf('y = %.3f x + %.3f', bestfit(1), bestfit(2));
text(x, y, theString, 'FontSize', 24);

[Shannon]

Great, I got this to work as soon as I realized that x and y in "text(x, y, theString, 'FontSize', 24)" refer to actual coordinates dependent on my x and y axis in the original plot.

Thanks!