  Many-Worlds quantum mechanics differs from standard quantum mechanics in that
in Many-Worlds, the wave function is a relative density of universes in the
multiverse amplitude rather than a probability amplitude. This means that in
Many-Worlds, the Born frequencies are approached rather than given a priori.
Thus in Many-Worlds the rate of approach to the final frequencies can be
calculated and compared with observation. I use Many-Worlds to derive the rate
of approach in the double slit experiment, and show that it agrees with
observation. Standard quantum theory has never been used to derive an approach
formula because it cannot be so used, as has been tacitly acknowledged for 70
years.
