@classmethod
    def student_t(cls, *marginals):
        """Scores ngrams using Student's t test with independence hypothesis
        for unigrams, as in Manning and Schutze 5.3.1.
        """
        return ((marginals[NGRAM] -
                  _product(marginals[UNIGRAMS]) /
                  (marginals[TOTAL] ** (1 - cls._n))) /
                (marginals[NGRAM] + _SMALL) ** .5)
dataset/ETHPy150Open nltk/nltk/nltk/metrics/association.py/NgramAssocMeasures.student_t/swapped operands of `-`