The major strength of our method is that it avoids the problems associated with heterogeneity of between-study variances (as a result of using the SD to calculate the SMD).
The exceptions were for a control ICC of 0.01 when the within-cluster variance increased as a result of the intervention for two of the distributional combinations.
To simplify the interpretation of the results, each contribution was normalized so that the sum equalled the total variance obtained as a result of the computation explained in the previous paragraphs.
Intracluster Correlation Coefficient (ICC) was not taken into account when calculating the sample size, because at the time of protocol development no study was available providing an estimate for variance inflation as a result of clustering.
The sequence in which the data were quantile-normalised and batch-corrected appeared to produce only marginal differences in the resulting variance components; as a result, all remaining corrections using mean-centring and ComBat were performed after quantile normalisation for consistency and to comply with the statistical assumptions of the latter [ 16].
Additionally, a covariate may also explain part of the genetic variance and as a result this may provide an indication for finding genes for this covariate, but of course the drawback is that with this covariate in the model the success of finding the latent gene (s) will be reduced.
Furthermore, the level of potential divergence as a result of differential sorting between lineages increases with genetic variance.
Results are shown in Table 3 which presents variance explained (R) at Step 1, incremental variance (Δ R) as a result of entering discomfort at Step 2, and total variance.
In this adolescent population approximately 42% of the variance in cortisol was as a result of within-participant variation and 58% as a result of between-participant variation.
Together, these results suggested (weakly) that a combination of mutation and selection determined the values of b: hypothetically, MutS may have increased b over the course of the experiment by increasing the variance in growth rates as a result of increased rates of mutation, whereas the lower slope of the Rif+ populations reflects the action of selection in the past.
