  The KASCADE experiment measures a high number of EAS observables with a large
degree of sampling of the electron-photon, muon, and hadron components. It
provides accurate data for an event-by-event analysis of the primary cosmic ray
flux in the energy range around the knee. The possibility of selecting samples
of enriched proton and iron induced extensive air showers by applying the
statistical techniques of multivariate analyses is scrutinized using detailed
Monte Carlo simulations of three different primaries. The purity and efficiency
of the proton and iron classified events is investigated. After obtaining
enriched samples from the measured data by application of the procedures the
reconstructed number of hadrons, hadronic energy and other parameters are
investigated in the primary energy range 1-10 PeV. By comparing these shower
parameters for purified proton and iron events, respectively, with simulated
distributions an attempt is made to check the validity of strong interaction
models at high energies.
