In addition, we used an internal validation procedure involving K-fold cross-validation on the training set itself [ 14].
It was used with the objective of selecting the attributes for each subset using an internal cross-validation.
To limit the computation time, the AdvISER-PYRO hyperparameters were not optimised for each iteration (using an internal cross-validation loop) but were kept constant across all iterations (Significant Contribution Threshold = 2; norm = 0.05, norm = 0).
An overfitted model could be detected through an assessment of model calibration using either an internal validation technique or external validation.
To calculate similarity between reverse transcriptase sequences for BRVM and KBMTL, we use the Gaussian kernel defined as k G (x i, x j ) = exp (− | | x i − x j | | 2 2 / s 2 ), where the kernel width s is chosen among 15, 20, 25, 30 and using an internal 5-fold cross-validation scheme on the training set.
The final model was evaluated using an internal leave-one-out cross-validation procedure (Hoek et al. 2008).
Second, we have focused on estimating and using predictions within the derivation dataset, but our approaches can also be extended to estimating and using predictions in an internal validation dataset (a different sample from the derivation dataset but within the same study population) or an external validation dataset (a sample independent of the derivation dataset (Moons et al., 2012a)).
For each sample, the PCR was done using a separate internal validation (β-globine PCR).
To assess the robustness of interaction models, we used two different strategies: an internal validation procedure based on bootstrap re-sampling methods [ 52] and a correction for multiple testing using the FDR principle [ 53].
To ensure that the calculated model of the recovering mice vs. sedentary mice is reliable and the observed clustering has not been obtained by chance, we performed an internal validation using 7-fold cross-validation [33].
