Table 2. A summary table of the GAMMs on the scaled second formant values (F2s) at the six time points of the vowel /æ/ of all the speakers in Hillenbrand et al. (1995) by the sex groups

F2s~mfordered+s(point, k=5)
+s(point, by=mfordered, k=5)
Parametric coefficients:
	Estimate	Std. Error	t-value	Pr(>|t|)
(Intercept)	5.63	0.02	314.7	<2e−16*
mforderedw	−0.05	0.02	−2.15	0.032*
Approximate significance of smooth terms:
	edf	Ref.df	F	p-value
s(point)	3.15	3.57	35.86	<2e−16*
s(point): mforderedw	3.07	3.51	13.65	153e-9*
R-sq.(adj)=0.505, Deviance explained=51.2%
GCV=0.082, Scale est.=0.081, n=534, * p<.05

GAMMs, generalized additive mixed models.