This code will do what you described:
New Table( "Untitled", Add Rows( 6 ),
New Column( "A", Numeric, "Continuous", Format( "Best", 12 ),
Set Values( [2, 3, 5, 4, 4, 1] ) ),
New Column( "B", Numeric, "Continuous", Format( "Best", 12 ),
Set Values( [5, 4, 5, 7, 4, 1] ) ),
New Column( "C", Character, "Nominal", Formula(
If( :A == 4 & :B == 4, "Good",
:A == 3 & :B == 3, "Bad",
:A == 1 & :B == 1, "Good"
)
)
)
);
Craig's link is excellent, especially because it discusses what happens with null values.