In this paper, we are concerned with randomized OBDDs and randomized
read-k-times branching programs. We present an example of a Boolean
function which has polynomial size randomized OBDDs with small,
one-sided error, but only non-deterministic read-once branching
programs of exponential size. Furthermore, we discuss a lower bound
technique for randomized OBDDs with two-sided error and prove an
exponential lower bound of this type. Our main result is an exponential
lower bound for randomized read-k-times branching programs with
two-sided error.