mastercode

%{
This code requires 2 or 3 vectors of equal size with your data.
Two vectors will be compared (the y-axis values) and the points above the line of best fit marked.
One of these two vectors you will provide; the other will be calculated from the line of best fit.
The second you must provide is the one that connects the two being compared (the x-axis values).
The potential third vector is a vector of strings for labeling the points.
If labeling is not desired, comment out or delete the code on line 64 and 66.
%}

%Fill in data here for x-axis, y-axis, and potential point labels.
%Keep in mind that all three must be the same size (data must match up).
x = []
y = []
names = ['']

%This plots the data.
plot(x,y,'ok')
hold on

%Uncomment below to label all points in black.
%Leave commented to label points only above line of best fit.
%labelpoints(x,y,names,'NW',0.15,1)

%This creates the line of best fit.
%If stats toolbox is not available, there is information on the internet for getting a line of best fit using polyfit.
lsline

%{
The "A" in the code below is a vector with the points on lsline corresponding with x-axis values of the y vector 
(in other words, the corresponding x vector values).
"A" is needed in order to find if the points of rating are above the line of best fit.
Later (not here), the x-axis values will be matched up and the y-axis values compared.
%}
%{
The code below creates a vector of zeros and prompts you for the slope and y int. of the line of best fit.
You can find that information in the "lsline equation" file of this repository.
It will also prompt you for the expected number of values you wish to include.
The number you enter should be the number corresponding to the place of the last x vector value you want.
This means it is possible to disclude values from the end, but not from the beginning or middle of the vector.
%}
val = input('expected number of values: ');
A = zeros(1,val);
k = 1;
m = input('slope: ');
b = input('y int.: ');
vector = input('vector for matching values: ');
%The below while loop replaces the zeros with the desired y values of the line.
%These values correspond to the matching x-axis values of your y vector, allowing future comparison.
while k < (val + 1)
    A(k) = (m*vector(k) + b);
    k = k + 1;
end

%{
COMPARISON
The code below marks the points above the line of best fit with an 'x' and
labels them with the strings from the 'names' vector.
The labels will appear red in the upper lefthand corner.
%}
p = 1;
while p < (val + 1)
    if y(p) > A(p)
        xUp = x(p);
        yUp = y(p);
        namesUp = names(p);
        plot(xUp,yUp,'gx')
        labelpoints(xUp,yUp,namesUp,'NW',0.15,1,'Color','r')
        hold on
    end
    p = p + 1;
end
%{
While loop explanation (if interested):
Inside the while loop is an if statement that compares the two vectors mentioned at the top comment.
The if statement starts from position 1 in the vectors.
If the y vector value in the corresponding position 'p' is larger than the y value of the 'A' vector,
the if statement plots it with a green x using its corresponding position from the x vector (xUp and yUp).
The if statement starts over, but at the next position (p + 1), 
continuing until it reaches the expected number of values that was previously entered (val).
This leaves you with a graph of red circles, some of which lie above the line of best fit and are specified with a green 'x.' 
%}