

cum3(boot)                                   R Documentation

_C_a_l_c_u_l_a_t_e _T_h_i_r_d _O_r_d_e_r _C_u_m_u_l_a_n_t_s

_D_e_s_c_r_i_p_t_i_o_n_:

     Calculates an estimate of the third cumulant, or skew-
     ness, of a vector.  Also, if more than one vector is
     specified, a product-moment of order 3 is estimated.

_U_s_a_g_e_:

     cum3(a, b=a, c=a, unbiased=T)

_A_r_g_u_m_e_n_t_s_:

       a: A vector of observations.

       b: Another vector of observations,  if not supplied
          it is set to the value of `a'.  If supplied then
          it must be the same length as `a'.

       c: Another vector of observations,  if not supplied
          it is set to the value of `a'.  If supplied then
          it must be the same length as `a'.

unbiased: A logical value indicating whether the unbiased
          estimator should be used.

_D_e_t_a_i_l_s_:

     The unbiased estimator uses a multiplier of
     `n/((n-1)*(n-2))' where `n' is the sample size, if
     `unbiased' is `FALSE' then a multiplier of `1/n' is
     used.  This is multiplied by `sum((a-mean(a))*(b-
     mean(b))*(c-mean(c)))' to give the required estimate.

_V_a_l_u_e_:

     The required estimate.

