ratpup                package:WWGbook                R Documentation

_r_a_t_p_u_p _d_a_t_a _i_n _C_h_a_p_t_e_r _3

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

     The data come from a study in which 30 female rats were randomly
     assigned to receive one of three doses (High, Low, or Control) of
     an experimental compound.

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

     data(ratpup)

_F_o_r_m_a_t:

     A data frame with 322 observations on the following 6 variables.

     _p_u_p._i_d : Unique identifier for each rat pup

     _w_e_i_g_h_t : Birth weight of the rat pup (the dependent variable)

     _s_e_x : Sex of the rat pup (Male, Female)

     _l_i_t_t_e_r : Litter ID number

     _l_i_t_s_i_z_e : Litter size (i.e., number of pups per litter)

     _t_r_e_a_t_m_e_n_t : Dose level of the experimental compound assigned to
          the litter (High, Low, Control)

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

     Pinheiro, J.C. and Bates, D.M., Mixed-effects models in S and
     S-PLUS, Springer-Verlag Inc., Berlin, New York, 2000.

     West, B., Welch, K. & Galecki, A, Linear Mixed Models: A Practical
     Guide Using Statistical Software, Chapman Hall / CRC Press, first
     edition, 2006.

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

     attach(ratpup)

     ###Figure 3.1:Boxplots to compare the distributions of birth weights for each treatment by sex combination graphically
     library(lattice)  # trellis graphics
     library(grid)

     bwplot(weight ~ sex|treatment, data=ratpup,aspect = 2, ylab="Birth Weights", 
         xlab="SEX",main = "Boxplots of birth weights for levels of treatment by sex")

