leaflength                package:drc                R Documentation

_L_e_a_f _l_e_n_g_t_h _o_f _b_a_r_l_e_y

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

     In an experiment barley was grown in a hydroponic solution with a
     herbicide.

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

     data(leaflength)

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

     A data frame with 42 observations on the following 2 variables.

     '_D_o_s_e' a numeric vector

     '_D_W' a numeric vector

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

     The dataset exhibits a large hormetical effect.

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

     Nina Cedergreen, Royal Veterinary and Agricultural University,
     Denmark.

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

     ## Fitting a hormesis model
     leaflength.crs4c1 <- drm(DW ~ Dose, data = leaflength, fct = CRS.4c())
     plot(fitted(leaflength.crs4c1), residuals(leaflength.crs4c1))

     leaflength.crs4c2 <- boxcox(drm(DW ~ Dose, data = leaflength, fct = CRS.4c()), method = "anova", plotit = FALSE)
     summary(leaflength.crs4c2)

     ## Plottinf fitted curve and original data
     plot(leaflength.crs4c2, broken = TRUE, conLevel = 0.001, type = "all", legend = FALSE, 
     ylab = "Produced leaf length (cm)", xlab = "Metsulfuron-methyl (mg/l)",
     main = "Hormesis: leaf length of barley")

