example, the BIC preferred model of heritability indicated that only two slopes were required to properly describe the trend. One slope is for the ages of 0 to 15, and therefore an arrow has been placed in the b0–3 column pointing toward the parameter estimate in the b3–15 column indicating that this slope applies in the age range of 0 to 3. Similarly, arrows pointing toward the earlier time point are presented for columns b30–60 and b60–90 indicating that the b15–30 slope applies during this area of the lifespan. Because parameter estimates are adjacent in the b3–15 and b15–30 columns, these can be interpreted as turning points in the spline models.
