Table 1. A summary table of the GAMMs on the scaled first formant values (F1s) at the six time points of the vowel /æ/ of all the speakers in Hillenbrand et al. (1995) by the sex groups

F1s~mfordered+s(point, k=5)
+s(point, by=mfordered, k=5)
Parametric coefficients:
	Estimate	Std. Error	t-value	Pr(>|t|)
(Intercept)	5.62	0.02	238.27	<2e−16*
mforderedw	−0.04	0.03	−1.23	0.221
Approximate significance of smooth terms:
	edf	Ref.df	F	p-value
s(point)	3.77	3.94	12.07	1.59e−9*
s(point): mforderedw	3.13	3.58	3.58	3.08e−7*
R-sq.(adj)=0.324, Deviance explained=33.4%
GCV=250.5, Scale est.=0.14, n=534, * p<.05

GAMMs, generalized additive mixed models.