  Recently, the CDF experiment at the Fermilab Tevatron has used complementary
methods to make multiple measurements of the singly produced top quark cross
section. All analyses use the same dataset with more than 2 fb^-1 of CDF data
and event selection based on W+2 or W+3 jet events with at least one b-tagged
jet. However, due to differences in analysis techniques these results are not
fully correlated and a combination provides improved experimental precision.
Two independent methods are used to combine the results. This combination
results in an improved measurement of the single top production cross section
and also the CKM matrix element V_tb.
