Table 1. Statistical analysis of the proportion of paramecium cells dispersing in experiments 1 and 2.

	Factor	F	d.f.	P
Experiment 1: Manipulation ofculture medium	Clone identity1	2.98	5, 17	0.041
	Log (population density in the experimental apparatus)1	.29	1, 17	0.023
	Log (population density previously contained by thedonor medium)	0.29	1, 21	0.60
	Clone identity of the donor medium population	1.67	5, 17	0.19
	Donor and assayed paramecia are from the sameor a different clone.	0.01	1, 21	0.92
Experiment 2: Manipulation ofpopulation density	Clone	14.1	2, 7	0.003
	Log (experimental population density)	12.6	1, 7	0.009
	Tube of origin [nested in Clone]	5.99	3, 7	0.024

The values provided for significant terms are those in the final model; for the others, the values are those when added one by one to the final model.

¹because clone and initial density are partly confounded, these two terms were not significant when added simultaneously to the model (SAS-type 3 fitting), but each was significant when added first in sequential (type 1) fitting procedure.