Function Estimate Std-Error Function Estimate Std-Error f1(age) -0.8406 0.1067 g1(age) -1.7838 0.8234 f2(age) -1.2020 0.0912 g2(age) -0.1625 0.0580 f3(age) -3.1655 0.1333 g3(age) 0.0021 0.0010 f4(age) -4.1235 0.1751 g4(age) -0.0939 0.0164 f5(age) -4.9521 0.1928 g5(age) 0.0339 0.0065 f6 (age) -4.8842 0.2479 g6(age) 0.0081 0.0035

Table 3: Estimates of fixed effects and their standard errors for different splines for the boys only data.