/* a simple regression */

load dta[16,5]  = gausstlk\longley1.asc;
n               = rows(dta);
k               = cols(dta);
x               = ones(n,1)~dta[.,1:k-2]~dta[.,k];  @intercept & selected cols@
y               = dta[.,k-1];                       @ pick out dependent@
v               = invpd(x'x);                       @symmetry saves time@
b               = v*(x'y);                          @ OLS coefficients@
e               = y - x*b;                          @ residuals@
sighat2         = e'e/(n-k);                        @ sigma hat squared@
se              = sqrt(sighat2*diag(v));            @ standard errors@
format 10,4;
"    coeff         se        t";
b~se~(b./se);