Test #1: Apparent magnitude versus redshift for galaxies

Applications of this test potentially suffer not only from Malmquist bias, but also because of extinction due to the intergalactic medium, making distant galaxies appear fainter than they otherwise would. But when these biases are compensated to the best of our ability, the observed relationship seems to agree well with expansion models that have a cosmic deceleration parameter q0 = 1 or slightly larger (closed universe). Of course, given that q0 is a free parameter, some form of the expansion hypothesis was sure to agree with observations. It is interesting to note that the static universe model, with no free parameters, also agrees with these observations. Taken in isolation, this test would therefore favor static universe models because they are simpler theories in the sense of Occam's Razor ("Invent no unnecessary hypotheses") or in the sense of Beysian analysis -- models with fewer free parameters are preferred, other things being equal.