Ecole Nationale Supérieure Agronomique de Montpellier ... - CIAM

TABLE 4. Type I error and power of the test of spatial independence between clusters of
diseased plants at two assessment dates on a lattice, in relation to a departure from the
assumptions of stationarity and independence of missing plants.
Border
effect c
Aggregation
with missing
plants d
Distance class 1 Distance class 2 Distance class 3 Distance class 4
Independent a Dependent b Independent Dependent Independent Dependent Independent Dependent
0.135 1.000 0.146 1.000 0.161 1.000 0.151 1.000
0.035 0.994 0.052 0.998 0.048 1.000 0.044 0.996
a The level of type I error is the probability to wrongly reject the (null) hypothesis of independence when
independent patterns are simulated.
b The power of the test is the probability to correctly reject the (null) hypothesis of independence when
dependent patterns are simulated.
c The simulated patterns is inhomogeneous, with an excessive number of diseased plants near one border of the
plot.
d Missing plants are simulated at random locations, and diseased plants at time 1 are simulated around them.
- 111 -