The Born Interpretation of the wave function gives only the relative frequencies as the number of observations approaches infinity. Using the Many-Worlds Interpretation of quantum mechanics, specifically the fact that there must exist other versions of ourselves in the multiverse, I show that the observed frequencies should approach the Born frequencies as 1/N, where N is the number of observations. In the body of the paper I state this convergence rate precisely as AN EASILY TESTABLE FORMULA. We can therefore test the central claim of the MWI by measuring the convergence rate to the final Born frequency. Conversely, the MWI allows us to calculate this convergence rate.