G (x) equals 1 p 2ˇ˙ e (x u0016) 2 = (2˙2) This is undoubtedly a curve that we usually also call the bell curve, where the mean is usually zero and the standard distribution is one 2. Error function The error function is the doubling of the integral of the Gaussian function, normalized between 0 and x = p second y = erf x = 2 p Z x 0 et2dt for x u00150; y [0; 1] in the cases when t = xp 2 3.