© 1981 by London Mathematical Society
Order of Magnitude of Moments of Sums of Random Variables
Department of Mathematics, Australian National University P.O. Box 4, Canberra, A.C.T., Australia 2600
Let X, X1, X2, ... be a sequence of independent and identically distributed random variables, set Sn =
and let med Sn denote the median of Sn. Suppose that 0 < p
2 and E|X|P <
. We derive the precise order of magnitude of E|Sn med Sn|p by obtaining a sequence of constants
p(n) which depends on the distribution of X in a very simple way and which satisfies C1
p(n)
E|Sn med Sn|p
C2
p(n) for positive constants C1 and C2 not depending on n. We obtain similar bounds for centring constants other than the median, and compare them.