coefZ                 package:mokken                 R Documentation

_C_o_m_p_u_t_a_t_i_o_n _o_f _Z-_V_a_l_u_e_s

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

     Computes Zij-values of item pairs, Zi-values of items, and Z-value
     of the entire scale, which are used to test whether Hij, Hi, and
     H, respectively, are significantly  greater than zero.

     Used in the function 'search.normal'

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

     coefZ(X)

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

       X: matrix or data frame of numeric data  containing the
          responses of 'nrow(X)' respondents to 'ncol(X)' items. 
          Missing values are not allowed

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

     Zij: matrix containing the z-values of the item-pairs

      Zi: vector containing z-values of the items

       Z: real z-value of the entire scale

_N_o_t_e:

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

     L. A. van der Ark a.vdark@uvt.nl

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

     Mokken, R. J. (1971)  _A Theory and Procedure of Scale Analysis_. 
     Berlin, Germany: De Gruyter.

     Molenaar, I.W. and Sijtsma, K. (2000)  _User's Manual MSP5 for
     Windows_ [Software manual]. Groningen, The Netherlands: IEC
     ProGAMMA.

     Van der Ark, L. A. (2007).  Mokken scale analysis in 'R'. 
     _Journal of Statistical Software_. <URL: http://www.jstatsoft.org>

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

     'coefH', 'search.normal'

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

     data(acl)
     acl.com <- acl[,1:10]
     coefH(acl.com)
     coefZ(acl.com)

