Table 1: Contingency tables for bin 50 of the PSR B1133+16 data, showing the frequency of occurrence of all possible combinations in the single pulses. The top table corresponds to the 4.85 GHz and the bottom table to the 1.41 GHz data.

4.85 GHz	Mode 1	Mode 2	Undefined
V +	390	452	1366
V -	659	436	1475

1.41 GHz	Mode 1	Mode 2	Undefined
V +	269	632	1506
V -	442	386	1563