Table 3.

Fixed effects estimates from mixed models involving quadratic and cubic growth functions

	Quadratic	Cubic
Intercept	7.426**	7.456**
Age	−0.016*	−0.020*
Age2	−0.002**	−0.001
Age3		−0.000*
Cohort	−0.042**	−0.043**
Age×cohort	−0.001	0.001
Age2×cohort	0.000**	0.000
Age3×cohort		−0.000**

Results computed for sample C (respondents born within the years 1909–1939), asterisks refer to statistical significance (t tests) with *P<0.01, **P<0.001