p = 2, a = . If Y has a half-normal distribution, Y -2 has a Levy distribution The Rayleigh distribution is a moment-tilted and scaled generalization of the half-normal distribution. Modified half-normal distribution with the pdf on is given as , where denotes the Fox-Wright Psi function. See also Half-t distribution Truncated normal distribution Folded normal distribution Rectified Gaussian distribution References Further reading External links Half-Normal Distribution at MathWorld (note that MathWorld uses the parameter Continuous distributions Normal distribution