How do I find the uncertainty in b and R^2

I have a to vaiables x and y and I preformed a linear fit on them and was given the uncertainty of yi to be 1.5 and already found the minimum chi-squared for the fit, how do I find the uncertainty in b and R^2 which I have already found?

This is what I did so far but I don't think it is right

This is what I did so far

x=[2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24];

y=[5.3, 14.4, 20.7, 30.1, 35.0, 41.3, 52.7, 55.7, 63.0, 72.1, 80.5, 87.9];

format long

cb=y/x;

yCalc = b1*x;

scatter(x,y)

hold on

plot(x,yCalc)

xlabel('xi')

ylabel('yi')

%Chi Squared value from derived equation to find smallest value

X22=1/1.5^2*(14.4-b*(4))^2;

%smallest value = 0.00002 from x2 and y2

%b value = 3.6017

%uncertainty in b

eb = sqrt(yi.^2*diff(b,yi)^2 + xi.^2*diff(b,xi)^2);

% R^2 value (R^2= 1- SSr/SSt)

Rsq=1 - sum((y-yCalc).^2)/sum((y - mean(y)).^2);

% R^2 value = 0.9965

%uncertainty in R^2

eRsq = sqrt(y.^2*diff(b,y)^2 + yCalc.^2*diff(b,yCalc)^2);