Resistance Inspection: Specification
WARNING: This page is about a different car, the 2004 Mazda 6. However, it is still accessible from the selected car via links, so may be relevant.
HO2S (RF, LF): 3.0-3.6 ohms (20°C {68°F})
HO2S (RR, LR): 5.0-7.0 ohms (20°C {68°F})