The hazard function for the normal distrbution, also known as the inverse Mill\’s ratio, is defined as h(x) = Z(x)/Q(x) = \sqrt{2/\pi \exp(-x^2 / 2) / \erfc(x/\sqrt 2)}. It decreases rapidly as x approaches -\infty and asymptotes to h(x) \sim x as x approaches +\infty.
err contains an estimate of the absolute error in the value z.
This function is from the GNU Scientific Library, see http://www.gnu.org/software/gsl/ for documentation.
Package: gsl