RatPupWeight package:nlme R Documentation _T_h_e _w_e_i_g_h_t _o_f _r_a_t _p_u_p_s _D_e_s_c_r_i_p_t_i_o_n: The 'RatPupWeight' data frame has 322 rows and 5 columns. _F_o_r_m_a_t: This data frame contains the following columns: _w_e_i_g_h_t a numeric vector _s_e_x a factor with levels 'Male' 'Female' _L_i_t_t_e_r an ordered factor with levels '9' < '8' < '7' < '4' < '2' < '10' < '1' < '3' < '5' < '6' < '21' < '22' < '24' < '27' < '26' < '25' < '23' < '17' < '11' < '14' < '13' < '15' < '16' < '20' < '19' < '18' < '12' _L_s_i_z_e a numeric vector _T_r_e_a_t_m_e_n_t an ordered factor with levels 'Control' < 'Low' < 'High' _S_o_u_r_c_e: Pinheiro, J. C. and Bates, D. M. (2000), _Mixed-Effects Models in S and S-PLUS_, Springer, New York.