  Type-B permutation tableaux are combinatorial objects introduced by Lam and
Williams that have an interesting connection with the partially asymmetric
simple exclusion process (PASEP). In this paper, we compute the expected value
of several statistics on these tableaux. Some of these computations are
motivated by a similar paper on permutation tableaux. Others are motivated by
the PASEP. In particular, we compute the expected number of rows, unrestricted
rows, diagonal ones, adjacent south steps, and adjacent west steps.
