Denote by S(n) the set of all distinct rooted binary trees with n unla
beled vertices. Define sigma(n) as a total height of a tree chosen at
random in the set S(n), assuming that all the possible choices are equ
ally probable. The total height of a tree is defined as the sum of the
heights of its vertices. The height of a vertex in a rooted tree is t
he distance from the vertex to the root of the tree, that is, the numb
er of edges in the path from the vertex to the root. This paper is con
cerned with the distribution and the moments of sigma(n) and their asy
mptotic behavior as n --> infinity). (C) 1994 Academic Press, Inc.