In this step, term candidates that pass the pre-filter are scored and ranked.
the null hypothesis that we expect to reject is that 'occurrence of a candidate is independent from occurrence of frequent Chi-Square (Matsuo and Ishizuka, 2003)  Rapid Keyword Extraction (Rose et al., 2010) Weirdness Weirdness (Ahmad et al., 1999) GlossEx Glossry Extraction (Park et al., 2002) termEx term Extraction (Sclano and Velardi, 2007) terms'.