Multivariate Approach for the Determination of the Energy ========================================================= Spectrum and Mass Composition of Cosmic Ray Flux ================================================ Abstract: --------- The KASCADE experiment measures a larger number of EAS observables with an improved degree of sampling of the electron-photon and muon components, with additional information about the hadronic core. It provides accurate data for an event-by-event analysis of the primary cosmic ray flux in the energy range of 10**14 - 10**16 eV. Nonparametric procedures for the estimation of the energy spectrum and mass composition are presented. The consistency of the analyses is checked by using different observables. The spectral indices below and above the knee are given. The analyses of measured data indicate a transition to a heavier composition at ~10PeV. The EAS differential size spectrum obtained by means of ANI installation located at Aragats Mt., 3200 m above the sea level is presented. The comparison with EAS TOP and KASCADE installations data is performed. The possibilities of the evaluating of the inelastic cross section for the interaction of protons and iron nuclei with air atoms at energies above the present accelerator range are discussed.