3.2.2 Internal-validation and External-validation
The Cross-validation calculated
values versus experimental values of
log η data were showed in
Figure 11 (a). The statistical parameters for validation are listed in
Table 3. The Figure 11 (a) shows that the experimental value is close to
the log η value calculated by Cross-validation. Table 3 shows
that the Q2 (0.9668), AARD (3.95%) andRMSE (0.1276) are acceptable, which suggests the good stability
and robustness of this η model.
7432 data points were randomly divided into the training set (5874 data
points) and the testing set (1468 data points). The calculated values
for the training set and the testing set with the experimental values
were showed in Figure 11 (b). The performance parameters for external
validation results are listed in Table 3. External validation results
showed that the R 2 of training set and testing
set were 0.9535 and 0.9607, and the AARD were 5.051 % and 4.743
%, respectively. These result showed that the QSPR model based on norm
descriptor was stable and has good predictive ability for ηprediction of ILs with diverse structures.