Skellam                 package:VGAM                 R Documentation

_T_h_e _S_k_e_l_l_a_m _D_i_s_t_r_i_b_u_t_i_o_n

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

     Density and random generation for the Skellam distribution.

_U_s_a_g_e:

     dskellam(x, mu1, mu2, log=FALSE)
     rskellam(n, mu1, mu2)

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

       x: vector of quantiles.

       n: number of observations. Must be a positive integer of length
          1.

mu1, mu2: See 'skellam'

     log: Logical; if TRUE, the logarithm is returned. 

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

     See 'skellam', the 'VGAM' family function for estimating the
     parameters, for the formula of the probability density function
     and other details.

_V_a_l_u_e:

     'dskellam' gives the density, and 'rskellam' generates random
     deviates.

_W_a_r_n_i_n_g:

     Numerical problems may occur for data if mu1 and/or mu2 are large.
     The normal approximation for this case has not been implemented
     yet.

_A_u_t_h_o_r(_s):

     T. W. Yee

_S_e_e _A_l_s_o:

     'skellam', 'dpois'.

_E_x_a_m_p_l_e_s:

     ## Not run: 
     mu1 = 1; mu2 = 2
     x = (-7):7
     plot(x, dskellam(x, mu1, mu2), type="h", las=1, col="blue",
          main=paste("Density of Skellam distribution with mu1=", mu1,
                     " and mu2=", mu2, sep=""))
     ## End(Not run)

