ToothGrowth             package:datasets             R Documentation

_T_h_e _E_f_f_e_c_t _o_f _V_i_t_a_m_i_n _C _o_n _T_o_o_t_h _G_r_o_w_t_h _i_n _G_u_i_n_e_a _P_i_g_s

_D_e_s_c_r_i_p_t_i_o_n:

     The response is the length of odontoblasts (teeth) in each of 10
     guinea pigs at each of three dose levels of Vitamin C (0.5, 1, and
     2 mg) with each of two delivery methods (orange juice or ascorbic
     acid).

_U_s_a_g_e:

     ToothGrowth

_F_o_r_m_a_t:

     A data frame with 60 observations on 3 variables.

       [,1]  len   numeric  Tooth length
       [,2]  supp  factor   Supplement type (VC or OJ).
       [,3]  dose  numeric  Dose in milligrams.

_S_o_u_r_c_e:

     C. I. Bliss (1952) _The Statistics of Bioassay_. Academic Press.

_R_e_f_e_r_e_n_c_e_s:

     McNeil, D. R. (1977) _Interactive Data Analysis_. New York: Wiley.

_E_x_a_m_p_l_e_s:

     require(graphics)
     coplot(len ~ dose | supp, data = ToothGrowth, panel = panel.smooth,
            xlab = "ToothGrowth data: length vs dose, given type of supplement")

