Two methods for looking at cosmological density on large scales are briefly described. The first takes galaxies observed in infrared, by the IRAS satellite. The second method, called POTENT by its inventors (Dekel and Bertschinger), uses the observed peculiar motions of galaxies to find the large scale peculiar velocity field. These two methods can be combined to test various theories of structure formation. First, though, we need to make sure that the velocity field derived from POTENT is consistent with the fractional overdensity field derived from IRAS. One way to compare them employs the non-parametric Wilcoxon-Mann-Whitney test.