

Lognormal {base}                             R Documentation

_T_h_e _L_o_g _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_:

     These functions provide information about the log nor-
     mal distribution whose logarithm has mean equal to
     `meanlog' and standard deviation equal to `sdlog'.
     `dlnorm' gives the density, `plnorm' gives the distri-
     bution function `qlnorm' gives the quantile function
     and `rlnorm' generates random deviates.

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

     dlnorm(x, meanlog = 0, sdlog = 1)
     plnorm(q, meanlog = 0, sdlog = 1)
     qlnorm(p, meanlog = 0, sdlog = 1)
     rlnorm(n, meanlog = 0, sdlog = 1)

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

     x,q: vector of quantiles.

       p: vector of probabilities.

       n: number of observations to generate.

meanlog,sdlog: mean and standard deviation of the distribu-
          tion on the log scale

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

     If `meanlog' or `sdlog' are not specified they assume
     the default values of `0' and `1' respectively.

     The log normal distribution has density

          f(x) = 1/(sqrt(2 pi) sigma x) e^-((log x - mu)^2 / (2 sigma^2))

     where mu and sigma are the mean and standard deviation
     of the logarithm.

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

     `dnorm' for the normal distribution.

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

     dlnorm(1) == dnorm(0)
     x <- rlnorm(1000)       # not yet always :
     all(abs(x  -  qlnorm(plnorm(x))) < 1e4 * .Machine$double.eps * x)

