MATLAB Solving MATLAB Sum Loop Issue with 2,187 Data Points

[Tone L]

So i want to calculate an r value 5 different times then find the mean of the 5 calculated values.
I have 2,187 data points. the first line of code generates 100 random points 1-2187.
The code has a bug but my major issue is it calculates r then loops again calculates r, loops again calculates r and there is no way to sum this. How can I edit my code. for i = 1:5
randomdata = round(rand(100,1).*2187);

xval = x(randomdata);
yval = y(randomdata);
numerator = length(xval)*nansum(xval.*yval) - (nansum(xval)*nansum(yval));

xsumsquared = nansum(xval)^2;
ysumsquared = nansum(yval)^2;
dddx = sqrt(length(xval)*nansum(xval.^2) - xsumsquared);
ddy = sqrt(length(xval)*nansum(yval.^2) - ysumsquared);
demonator = dddx * ddy;
r = numerator/demonator;


end

thanks

 

[FactChecker]

Set a variable sum_r =0; before all your code. Total sum_r = sum_r + r; right after r is calculated. Display sum_r after your code.