using a forloop to create vertical lines between regression line and scatter plot

I have these X and Y variables

X=[1;2;3;4;5;6;7;8;9;10];

Y=[17;7;15;13;17;34;35;30;46;31];

I created a scatter plot using

scatter(X,Y,'+','r')

and this is the line of best fit (regression line)

Y =5.9333+3.3758*X;

i need to draw VERTICAL lines from the observed values given in the scatter plot to the fitted line, and measure their distance.

how can I do this using a forloop with MATLAB please? (was specifically asked to use a forloop)

[Elisa Caruana]

I managed to do it, I had a mistake in labelling more than one thing as Y.

Thanks for the help!

Answer 1

[Voss]

X=[1;2;3;4;5;6;7;8;9;10];
Y=[17;7;15;13;17;34;35;30;46;31];
% I created a scatter plot using 
scatter(X,Y,'+','r')
% and this is the line of best fit (regression line)
% Y =5.9333+3.3758*X;

% calculate and plot the fitted line:
mb = polyfit(X,Y,1)

mb = 1×2

3.3758 5.9333

Y_fit = polyval(mb,X);
hold on
plot(X,Y_fit,'--b')

% construct and plot the vertical lines:
% (without for loop)
nans = NaN(numel(X),1);
xdata = [X X nans].';
ydata = [Y Y_fit nans].';
plot(xdata(:),ydata(:),'g');

% calculate the lengths of the vertical line segments:
len = abs(Y-Y_fit)

len = 10×1

7.6909 5.6848 1.0606 6.4364 5.8121 7.8121 5.4364 2.9394 9.6848 8.6909

% (put the scatter plot on top of the others)
set(gca(),'Children',flip(get(gca(),'Children')))

[Star Strider]

This is the complete solution to a homework problem.

Note that the regression equation is provided. It does not have to be calculated.

[Voss]

I wanted to make sure the provided equation was correct.

I'll edit it to remove the loop, thus rendering the solution incomplete.