Rayleigh density is given as: ("c" is a real constant) f(x)=[x / c ] exp(-x / (2 c)) u(x) where u(x) is unit-step function The kurtosis of a distribution is often measured by means of quantity B = E{(x-)}/6, evaluate for Rayleigh Density. Do not use Gamma Function formulas for moments of Rayleigh p.d.f. The formulas of the moments (depends on "c") should be proven explicitly by integration by parts etc.