ols d1 const d2 and the std error of d2 is 0.351919 d1 1 -0.9371 2 -0.40054 3 1.963222 4 -0.3328 5 -0.82194 6 1.085598 7 -0.9985 8 0.763004 9 -0.94785 10 0.047204 d2 1 -0.26785 2 -0.67142 3 -1.07196 4 0.891262 5 0.558466 6 -0.26347 7 0.822125 8 -0.17638 9 0.586626 10 -0.3612 Use s = sqrt[ ∑ ((e_i)^2/(n-2)) / (∑ (x_i - xbar)^2) ] for manually calculating the std error and the value is 0.88583 and does not match the one on gretl What are the proper steps to do the manual calculating ?