snails                package: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 temperature 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 completely randomized design.  At
     the end of the exposure time the snails were tested to see if they
     had survived; 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.

