methyl                 package:MCPAN                 R Documentation

_N_T_P _b_i_o_a_s_s_a_y _d_a_t_a: _e_f_f_e_c_t _o_f _m_e_t_h_y_l_e_u_g_e_n_o_l _o_n _s_k_i_n _f_i_b_r_o_m_a

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

     NTP bioassay of methyleugenol: 200 male rats were randomly
     assigned to 4 treatment groups with balanced sample size 50.
     Individuals in treatment group 0, 1, 2, and 3 received doses of 0,
     37, 75, and 150 mg methyleugenol per kg body weight, respectively.
     The response variable 'tumour' is the presence of skin fibroma at
     time of death. The variable 'death' gives individual time of
     death, with a final sacrifice of surviving animals at 730 days
     after begin of the assay.

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

     data(methyl)

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

     A data frame with 200 observations on the following 3 variables.

     '_g_r_o_u_p' a factor with levels '0' '1' '2' '3', specifying dose
          groups 0, 37, 75, and 150 mg/kg, respectively

     '_t_u_m_o_u_r' a numeric vector, specifying whether a tumour was present
          at time of death

     '_d_e_a_t_h' a numeric vector, specifying the time of death

_S_o_u_r_c_e:

     National toxicology program (2000).

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

     SD Peddada, GE Dinse, JK Haseman (2005): A survival-adjusted
     quantal response test for comparing tumour incidence rates.
     Applied Statistics 54, 51-61.

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

     data(methyl)
     # raw tumour proportions:
     table(methyl[c("group", "tumour")])

     # time of death:
     boxplot(death~group, data=methyl, horizontal=TRUE)

