snorm                  package:VGAM                  R Documentation

_S_k_e_w-_N_o_r_m_a_l _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 skew-normal distribution.

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

     dsnorm(x, location = 0, scale = 1, shape = 0)
     rsnorm(n, location = 0, scale = 1, shape = 0)

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

       x: vector of quantiles.

       n: number of observations. Must be a single positive integer. 

location: The location parameter xi. A vector.  

   scale: The scale parameter w. A positive vector. 

   shape: The shape parameter. It is called alpha in 'skewnormal1'. 

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

     See 'skewnormal1', which currently only estimates the shape
     parameter. More generally here, Z = xi + w * Y where Y has a
     standard skew-normal distribution (see 'skewnormal1'), xi is the
     location parameter and w is the scale parameter.

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

     'dsnorm' gives the density, 'rsnorm' generates random deviates.

_N_o_t_e:

     The default values of all three parameters corresponds to the
     skew-normal being the standard normal distribution.

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

     T. W. Yee

_R_e_f_e_r_e_n_c_e_s:

     <URL: http://tango.stat.unipd.it/SN>.

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

     'skewnormal1'.

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

     ## Not run: 
     n = 200   # grid resolution
     shape = 7
     x = seq(-4, 4, len=n)
     plot(x, dsnorm(x, shape=shape), type="l", col="blue", las=1, ylab="")
     abline(v=0, h=0, lty="dashed", col="darkgreen")
     lines(x, dnorm(x), col="red")
     legend(-3.5, 0.6, leg=c(paste("Blue=dsnorm(x, ", shape,")", sep=""),
            "standard normal density"), lty=1, col=c("blue","red"))
     ## End(Not run)

