A fundamental question in computational complexity theory is whether all polynomial time randomized algorithms for decision problems can be deterministically simulated in polynomial time. The existence of such a simulation would imply that BPP = P. To perform such a simulation, it is sufficient to construct pseudorandom generators against the family F of all circuits of size "s"("n") whose inputs have length "n" and output a single bit, where "s"("n") is an arbitrary polynomial, the seed length of the pseudorandom generator is O(log "n") and its bias is ⅓.