Next, we fit the re-parameterized Equation 16 to the data. Parameter estimates and their SEs and CIs are shown in the right side of Table 1. The point estimate of the cross-over point Ĉ, (SE = 0.09), 95% CI [2.55, 2.92], fell just below the sample mean on X1 (M = 2.83). The lower limit of the CI for Ĉ fell 1.17 SD units below the sample mean of childcare quality and the upper limit fell 0.38 SD units above the sample mean, so the CI covers values in the middle of the range of X1 in the sample. Thus, both point and interval estimates of the cross-over point support a conclusion that the interaction was disordinal, providing stronger support for differential-susceptibility model than for diathesis-stress.
