Table 1.

Parameter Estimates Derived by Fitting Equation 8 to the Average Response Rates From Experiments 2 and 3

	Parameter
Condition	a	δ	β	$R_{\mathrm{a}}^2$
Experiment 2
5-s millet	40	0.34	.6	.89
Popcorn	153	0.41	.6	.82
2.5-s millet	25	0.34	.6	.97
5-s milo	53	0.29	.4	.89
5-s millet	39	0.34	.6	.90
Experiment 3
Key peck	64	0.32	.6	.91
Treadle press	196	1.12	.5	.92

Note. $R_{\mathrm{a}}^2$ is the adjusted coefficient of multiple determination.