twinan90                 package:gap                 R Documentation

_C_l_a_s_s_i_c _t_w_i_n _m_o_d_e_l_s

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

     Classic twin models

     The function also allows for test for normality and Box-Cox
     transformation. It further allows for output data in FISHER
     format.

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

     twinan90(mzdat,dzdat,vname='mzdz',xlamb=1,const=0,vmiss=-9,path=1,
                ped=0,nvar=1,form='((1x,a1,5x,F6.2))')

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

   mzdat: two columns of data for MZ twins

   dzdat: two columns of data for DZ twins

   vname: variable name

   xlamb: the Box-Cox transformation parameter

   const: constant to be added to each data value

   vmiss: missing value indicator

    path: path analysis to be conducted

     ped: if 1, to output data in FISHER format

    nvar: number of variables in the data file

    form: the Fortran format for the data file

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

     The returned values is in a list with two components, while the
     MLEs are in two system files:

      h2: The heritability estimate based on 2(rMZ-rDZ), where rMZ and
          rDZ are the intraclass correlation coefficients for MZ and DZ
          twin pairs

    seh2: The standard error for the above statistic

vname.log: the diagnostic file

vname.out: the output file

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

     Williams CJ, Christian JC, Norton JA Jr. (1992) TWINAN90: A
     FORTRAN program  for conducting ANOVA-based and likelihood-based
     analyses of twin data. Computer Methods and  Programs in
     Biomedicine 38:(2-3):167-176 

     Williams CJ (1993). On the covariance between parameter estimates
     in models of twin  data. Biometrics. 49(2):557-68

_N_o_t_e:

     built on newtw5.for

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

     Chris Williams, Jing Hua Zhao

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

     ## Not run: 
     mzdz <- matrix(scan("mzdz.dat",skip=1),ncol=2,byrow=T)
     mzdat <- mzdz[1:131,]
     dzdat <- mzdz[132:206,]
     twinan90(mzdat,dzdat,xlamb=2)
     ## End(Not run)

