fitz             package:hyperdirichlet             R Documentation

_F_i_t_z_m_a_u_r_i_c_e

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

     Hyperdirichlet distribution corresponding to a dataset of
     Fitzmaurice et al

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

     fitz(dat , include.missing=TRUE , validated=NULL)

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

     dat: A vector corresponding to either male or female data

include.missing: Boolean, with default 'TRUE' meaning to return the
          likelihood function for the data including the missing cases,
          and 'FALSE' meaning to include only the data corresponding to
          complete cases

validated: Boolean, with 'TRUE' meaning to omit the checks (OK if all
          elements of 'dat' are non-negative) and 'FALSE' meaning to
          check them all (time-consuming)

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

     Fitzmaurice considered childhood obesity.  See the reference for
     further details.

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

     Returns a hyperdirichlet distribution (without normalizing factor)
     corresponding to the observations, either male or female,  made by
     Fitzmaurice et al.

_N_o_t_e:

     Pat Altham originally spotted that this dataset could be
     represented using the hyperdirichlet distribution.

     The functional form for replacement '[<-'() is used because it
     is possible to set the 'validated' argument to 'TRUE': this
     suppresses the computationally intensive checking that the
     distribution is proper.

     *warning.*  Setting 'validated' to 'TRUE' is not recommended in
     general.  It is OK here because the function knows that no
     elements of 'dat' is negative.

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

     Robin K. S. Hankin

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

     G. M. Fitzmaurice, N. M. Laird, and S. R. Lipsitz 1994. Analysing
     incomplete longitudinal binary responses: a likelihood-based
     approach. _Biometrics_, volume 50, pp601-612.

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

       boys  <- c(20,7,9,8, 8, 8,15,150,13,3,2,42,3,1, 6,16,11,1,3,38,14,55,4,33,7,45)
       girls <- c(21,6,6,2,19,13,14,154, 8,1,4,47,4,0,16, 3,11,1,3,25,13,39,5,23,7,47)

       male <- fitz(boys)
       maximum_likelihood(male)

