cor function - RDocumentation
www.rdocumentation.org › versions › 3The denominator \ (n - 1\) is used which gives an unbiased estimator of the (co)variance for i.i.d. observations. These functions return NA when there is only one observation (whereas S-PLUS has been returning NaN ). For cor (), if method is "kendall" or "spearman", Kendall's \ (\tau\) or Spearman's \ (\rho\) statistic is used to estimate a ...