coop package:MASS R Documentation _C_o-_o_p_e_r_a_t_i_v_e _T_r_i_a_l _i_n _A_n_a_l_y_t_i_c_a_l _C_h_e_m_i_s_t_r_y _D_e_s_c_r_i_p_t_i_o_n: Seven specimens were sent to 6 laboratories in 3 separate batches and each analysed for Analyte. Each analysis was duplicated. _U_s_a_g_e: coop _F_o_r_m_a_t: This data frame contains the following columns: '_L_a_b' Laboratory, 'L1', 'L2', ..., 'L6'. '_S_p_c' Specimen, 'S1', 'S2', ..., 'S7'. '_B_a_t' Batch, 'B1', 'B2', 'B3' (nested within 'Spc/Lab'), '_C_o_n_c' Concentration of Analyte in g/kg. _S_o_u_r_c_e: Analytical Methods Committee (1987) Recommendations for the conduct and interpretation of co-operative trials, _The Analyst_ *112*, 679-686. _R_e_f_e_r_e_n_c_e_s: Venables, W. N. and Ripley, B. D. (2002) _Modern Applied Statistics with S._ Fourth edition. Springer. _S_e_e _A_l_s_o: 'chem', 'abbey'.