PlantGrowth             package:datasets             R Documentation

_R_e_s_u_l_t_s _f_r_o_m _a_n _E_x_p_e_r_i_m_e_n_t _o_n _P_l_a_n_t _G_r_o_w_t_h

_D_e_s_c_r_i_p_t_i_o_n:

     Results from an experiment to compare yields (as measured by dried
     weight of plants) obtained under a control and two different
     treatment conditions.

_U_s_a_g_e:

     PlantGrowth

_F_o_r_m_a_t:

     A data frame of 30 cases on 2 variables.

       [, 1]  weight  numeric
       [, 2]  group   factor

     The levels of 'group' are 'ctrl', 'trt1', and 'trt2'.

_S_o_u_r_c_e:

     Dobson, A. J. (1983) _An Introduction to Statistical Modelling_.
     London: Chapman and Hall.

_E_x_a_m_p_l_e_s:

     ## One factor ANOVA example from Dobson's book, cf. Table 7.4:
     require(stats); require(graphics)
     boxplot(weight ~ group, data = PlantGrowth, main = "PlantGrowth data",
             ylab = "Dried weight of plants", col = "lightgray",
             notch = TRUE, varwidth = TRUE)
     anova(lm(weight ~ group, data = PlantGrowth))