Nonparametric discriminant analysis for antisymmetric averages of the east–west and north–south travel-time differences, (top) and (bottom) in filter TD3, in the same format as Figure 1. Left: the density estimates for NE regions for both and , 24.5 hr before the emergence time are peaked close to 0 s and are fairly symmetric; the density estimates for PE regions are both peaked close to 1 s. Right: given the uncertainties, there is no obvious trend in and only weak evidence for a trend toward worse performance closer to emergence for .