Neutrino cosmology is a very interesting field of research,where properties of some of the smallest constituents of the universeare probed by the very largest structures of the universe; large scalestructures of the size of clusters of galaxiesand the cosmic microwave background radiation. Cosmology has, over thelast decade, provided strong limits on the total neutrino mass,assuming that the splitting of the neutrino mass contributesnegligible to the effect of neutrinos on cosmology. There is, however,a splitting between the masses of the individual neutrino masseigenstates, as shown by neutrino oscillation experiments, andalthough the mass square difference is measured, the ordering of themasses is still to be determined.
As cosmology has provided stronger limits on the totalneutrino mass than other experiments, it is hoped that cosmology alsocan solve the mystery of the neutrino mass hierarchy. The goal of thisthesis is to investigate the effect of neutrino mass hierarchy oncosmology, by translating the results of neutrinomass experiments to a hierarchy dependent prior on the total neutrinomass, which is then applied to cosmological parameter likelihood distributions.It is found that adding such a hierarchy dependent prior does notallow for a determination of the neutrino mass hierarchy from threechosen parameters; thespectral index, the baryon acoustic oscillation parameter A(z) and the fluctuation amplitude on cluster scales. This supports the general assumption that the neutrino masshierarchy can be neglected in cosmology.