Fitting lines to points in the plane

We seek for lines of minimal distance to finitely many points in the plane. The distance between a line and a set of points is defined by the L^p-norm, 1\leq p\leq \infty, of the vector of vertical or orthogonal distances from the single points to the line. The known properties of optimal lines are deduced by elementary considerations and represented using a uniform language for the different choices to define the distance from a line to a set of points.