"Linear regression" Y = ( 6.30, -- U228 14.4, -- U230 21.5, -- U232 29.7, -- U234 34.2, -- U236 39.5, -- U238 7.52, -- Th226 17.9, -- Th228 28.5, -- Th230 40.6) -- Th232 Z = (90,90,90,90,90,90,88,88,88,88) Z = float(Z) E = ( 6.80, 5.99, 5.41, 4.86, 4.57, 4.27, 6.45, 5.52, 4.77, 4.08) -- design matrix X = zero(3,10) X[1] = Z / sqrt(E) X[2] = Z^(2/3) X[3] = X[3] + 1 -- ordinary least squares beta = dot(inv(dot(X,transpose(X))),X,Y) beta Yhat = dot(beta,X) Yhat "Coefficient of determination (R squared)" Ybar = sum(Y) / dim(Y) RSS = sum((Y - Yhat)^2) -- residual sum of squares TSS = sum((Y - Ybar)^2) -- total sum of squares 1 - RSS / TSS Run