Both Nikon W300 and Ricoh WG-70 have 16.0 MP resolution sensors but Nikon W300's sensor is 1/2.3 (6.17 x 4.55 mm ) and Ricoh WG-70's sensor is (1/2. ).
Since Nikon W300's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Ricoh WG-70.
Below you can see the W300 and WG-70 sensor size comparison.
As seen above, Nikon W300 has a infx Larger sensor area than Ricoh WG-70. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.