methionine                package:drc                R Documentation

_W_e_i_g_h_t _g_a_i_n _f_o_r _d_i_f_f_e_r_e_n_t _m_e_t_h_i_o_n_i_n_e _s_o_u_r_c_e_s

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

     Data consist of average body weight gain of chickens being treated
      with one of the two methionine sources DLM and HMTBA.

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

     data(methionine)

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

     A data frame with 9 observations on the following 3 variables:

     '_p_r_o_d_u_c_t' a factor with levels 'control', 'DLM' and 'MHA' denoting
          the treatments

     '_d_o_s_e' a numeric vector of methionine dose

     '_g_a_i_n' a numeric vector of average body weight gain

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

     The dataset contains a common control measurement for the two
     treatments. More examples using this dataset are found under
     'AR.2' and 'MM.2'.

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

     Kratzer. D. D. and Littell, R. C. (2006) Appropriate Statistical
     Methods to Compare  Dose Responses of Methionine Sources, _Poultry
     Science_, *85*, 947-954.

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

     ## Fitting model with constraint on one parameter 
     met.ar.m1 <- drm(gain~dose, product, data = methionine, 
     fct = AR.3(), pmodels = list(~1, ~factor(product), ~factor(product)), 
     upperl = c(Inf, Inf, 1700, Inf, Inf)) 

     plot(met.ar.m1, xlim=c(0,0.3), ylim=c(1450, 1800))
     abline(h=1700, lty=1)

     summary(met.ar.m1)

