Table 1. Target detection accuracy (mean and standard error) as a function of probe probability, probe presence and probe position when the target was present.

Probe Probability	Probe Presence
	Yes		No
	+2	+8
80% at +2 & 20% at +8	.91 (.02)	.93 (.02)	.90 (.02)
20% at +2 & 80% at +8	.90 (.02)	.92 (.02)	.90 (.02)