Table 2.

Observed and predicted numbers of nematodes at less than 5 mm, 5–10 mm, 10–15 mm and greater than 15 mm distance from the release point, corresponding to 5, 10 and 15 min. (‘New model’ stands for the model developed here; ‘S–G model’ is the model developed by Skalski & Gilliam (2000) in which four groups with diffusion coefficients D₁=0.026, D₂=0.147, D₃=0.433, D₄=1.647 were considered; ‘normal diffusion model’ is the classical model with diffusion coefficient D=0.118. The p-values represent the probabilities associated with the chi-squared goodness-of-fit test of the observed data against the predicted values provided by the different models.)

time	section
	<5 mm	5–10 mm	10–15 mm	>15 mm	p-value
5 min
observed	11	4	5	5	–
new model	10.86	6.55	3.54	3.97	0.601
S–G model	5.32	5.72	3.46	10.48	0.018
normal diffusion	4.42	9.10	7.13	4.33	0.004
10 min
observed	9	4	2	10
new model	7.88	5.91	3.93	7.24	0.425
S–G model	2.97	4.93	3.38	13.70	0.003
normal diffusion	2.19	5.49	6.37	10.92	0.000
15 min
observed	6	4	4	11
new model	6.74	5.44	3.88	8.83	0.798
S–G model	2.23	4.29	3.40	15.05	0.056
normal diffusion	1.60	4.21	5.40	13.77	0.005