Table 3 The goodness of fit, as measured by the R2, for all six regression models with FE alone as well as the R2 and the intra-class correlation (ICC) for the model with both FE and RE.

From: Statistical Modeling of Heart Rate Variability to Unravel the Factors Affecting Autonomic Regulation in Preterm Infants

Period IV R2 with FE R2 with FE and RE ICC
Pre-KC SDNN 0.06 0.18 0.15
pDec 0.12 0.26 0.19
SDDec 0.04 0.09 0.07
During-KC SDNN 0.13 0.23 0.12
pDec 0.29 0.42 0.19
SDDec 0.12 0.17 0.08