Two analytical methodologies are used for the analysis of the NMR data of alginates. The samples are shown to be compositionally heterogeneous, and the NMR data can be treated with either a discrete or a continuous statistical model. The unfractionated alginate is found to contain at least four components: two mostly homopolymer blocks, one somewhat alternating copolymer block, and one or more random copolymer blocks. Other information available includes chemical composition distribution, component statistics and reaction probabilities, and average M and G block lengths.