How to plot best fit line?

I have 1700 plot of data in graph. How do I plot the line of best fit? I stored the x and y data in table and the plot them. From the graph, I can see that the graph plotting is upwards. I have read other answers for this kind of question but still confused. Please help. Thank you.

x = score;
y = MOS;
scatter(x,y)
xlabel('score')
ylabel('MOS')

Answer 1

[Image Analyst]

Use polyfit() and polyval():

% Get coefficients of a line fit through the data.
coefficients = polyfit(x, y, 1);
% Create a new x axis with exactly 1000 points (or whatever you want).
xFit = linspace(min(x), max(x), 1000);
% Get the estimated yFit value for each of those 1000 new x locations.
yFit = polyval(coefficients , xFit);
% Plot everything.
plot(x, y, 'b.', 'MarkerSize', 15); % Plot training data.
hold on; % Set hold on so the next plot does not blow away the one we just drew.
plot(xFit, yFit, 'r-', 'LineWidth', 2); % Plot fitted line.
grid on;

See attached for a full demo.

[Sidharth Thomas]

Thanks. This works perfectly.

[Sahil Bharti]

Thanks. it was usefull to me as well

[Miles]

Thank you!

Answer 2

[Jos (10584)]

if it is just for plotting, the command lsline would do.

x = 1:10 ; y = 2* x + 3 ;
plot(x, y, 'bo') ;
lsline

[optoengineer2]

lsline works only with "Statistics and Machine Learning Toolbox"