Research on improving water quality using two experimental statistical methods Mihail Aurel Ţîţu, Andrei Victor Sandu, Costel Ceocea, Alina Bianca Pop, Ştefan Ţîţu and Alexandra Maria Matia MATEC Web Conf., 178 (2018) 08014 Published online: 24 July 2018 DOI: 10.1051/matecconf/201817808014