Multishell models used for calculating the elementary scattering amplitude from micelles are replaced by the Fourier transforms of the probability density functions of finding the hydrophobic (methyl and methylene) groups as well as the headgroup and counterions at a particular distance from the micellar center. Model variables are the aggregation number and two width parameters respectively characterizing the Gaussian core and the exponential counterion profiles. Application of the model to almost spherical Sodium nonyl-, decyl and undecyl sulfate micelles leads to reasonable best-fit values. Aggregation numbers are tested by a recent thermodynamic model of micellization. Within the limits set by the finite resolution of the method, the group-density functions render possible to determine the spatial distribution of any physical quantity inside and around the micelles that depends only on the number of the molecular groups present. As an example, the relative dielectric permittivity is discussed.