

snails(Rnotes)                               R Documentation

_T_h_e _S_n_a_i_l _M_o_r_t_a_l_i_t_y _D_a_t_a

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

     Groups of 20 snails were held for periods of 1, 2, 3 or
     4 weeks in carefully controlled conditions of tempera-
     ture and relative humidity.

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

     There were two species of snail, A and B, and the
     experiment was designed as a 4 by 3 by 4 by 2 com-
     pletely randomized design.  At the end of the exposure
     time the snails were tested to see if they had sur-
     vived; the process itself is fatal for the animals.
     The object of the exercise was to model the probability
     of survival in terms of the stimulus variables, and in
     particular to test for differences between species.

     The data are unusual in that in most cases fatalities
     during the experiment were fairly small.

_V_a_l_u_e_:

     The data frame contains the following components:

 Species: Snail species A (1) or B (2)

Exposure: Exposure in weeks

 Rel.Hum: Relative humidity (4 levels)

    Temp: Temperature, in degrees Celsius (3 levels)

  Deaths: Number of deaths

       N: Number of snails exposed

_C_A_T_E_G_O_R_Y_:

     Generalized Linear Modelling

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

     Zoology Department, The University of Adelaide.

