perversity vs skewness

perversity

noun
  • A perverse act. 

  • The quality of being perverse. 

skewness

noun
  • The property of being skew. 

  • A measure of the asymmetry of the probability distribution of a real-valued random variable; is the third standardized moment, defined as scriptstyle 𝛾₁=(𝜇₃)/(𝜎³),! where 𝜇₃ is the third moment about the mean and 𝜎 is the standard deviation. 

How often have the words perversity and skewness occurred in a corpus of books? (source: Google Ngram Viewer )