_gslope is an extension to generate (egen) function. egen result = slope(y1 x2 y2 x2 ... yk xk) [if expr] [in range] [, coo min(#) ] returns the slopes of a row-wise ols-regression of y on x (with at most k observations). min(#) specifies that only cases with at least # non-missing (y,x) pairs should be included, 2<=#<=k. coo is short for min(k). For accuracy in computations, the method of "provisional means" is used in double precision.