Estimator of the second order regular variation parameter \(\rho \leq 0\) parameter for heavy-tailed data based on ratio of kernel goodness-of-fit statistics.
     
    
    
    Arguments
- xdat
- vector of positive observations 
- k
- number of highest order statistics to use for estimation 
 
    
    References
    Goegebeur, Y., J. Beirlant and T. de Wet (2008). Linking Pareto-tail kernel goodness-of-fit statistics with tail index at optimal threshold and second order estimation.  REVSTAT-Statistical Journal, 6(1), 51-69. <doi:10.57805/revstat.v6i1.57>