

replications {base}                          R Documentation

_N_u_m_b_e_r _o_f _R_e_p_l_i_c_a_t_i_o_n_s _o_f _T_e_r_m_s

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

     Returns a vector or a list of the number of replicates
     for each term in the formula.

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

     replications(formula, data=NULL, na.action=na.fail)

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

 formula: a formula or a terms object or a data frame

    data: a data frame used  to  find  the  objects in `for-
          mula'

na.action: function for handling missing values

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

     If `formula' is a data frame and `data' is missing,
     `formula' is used for `data' with the formula `~ .'.

_V_a_l_u_e_:

     A vector or list with one entry for each term in the
     formula giving the number(s) of replications for each
     level. If all levels are balanced (have the same number
     of replications) the result is a vector, otherwise it
     is a list with a component for each terms, as a vector,
     matrix or array as required.

     A test for balance is `!is.list(replications(for-
     mula,data))'.

_A_u_t_h_o_r_(_s_)_:

     B.D. Ripley

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

     `model.tables'

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

     ## From Venables and Ripley (1997) p.210.
     N <- c(0,1,0,1,1,1,0,0,0,1,1,0,1,1,0,0,1,0,1,0,1,1,0,0)
     P <- c(1,1,0,0,0,1,0,1,1,1,0,0,0,1,0,1,1,0,0,1,0,1,1,0)
     K <- c(1,0,0,1,0,1,1,0,0,1,0,1,0,1,1,0,0,0,1,1,1,0,1,0)
     yield <- c(49.5,62.8,46.8,57.0,59.8,58.5,55.5,56.0,62.8,55.8,69.5,
     55.0, 62.0,48.8,45.5,44.2,52.0,51.5,49.8,48.8,57.2,59.0,53.2,56.0)

     npk <- data.frame(block=gl(6,4), N=factor(N), P=factor(P),
                       K=factor(K), yield=yield)
     replications(~. - yield, npk)

