Chapter 3.3, Problem 34E

Suppose that the number of plants of a particular type found in a rectangular sampling region (called a quadrat by ecologists) in a certain geographic area is an rv X with pmf

$p(x)\text{ = }\{\begin{array}{l}c/x^{3}x\text{ = 1, 2, 3, }\mathrm{...}\\ \text{0 otherwise}\end{array}$

Is E(X) finite? Justify your answer (this is another distribution that statisticians would call heavy-tailed).