The model heterogeneity error is computed by averaging, over all tumor samples, the mean absolute error of the mixing proportions θ d of the cancer cells and the true site of origin.
Ratios below 1/125 are not recommended because of poorer reproducibility (substrate heterogeneity, weighing errors), as well as issues with the detection of low Pb concentrations during subsequent analysis.
It also enables us to address important methodological issues, such as firm-level time-invariant heterogeneity, measurement errors, reverse causality, feedback effects and state dependence of firm productivity.
For example, it could mean that compounds have been extracted from some hitherto overlooked important source or, on the other hand, could have been generated as a consequence of heterogeneity and/or errors in structural representation.
These procedures are supposed to correct for unobserved country-specific heterogeneity, measurement errors and endogeneity.
Multivariable Cox regression was also used for sensitivity analysis (control for heterogeneity and errors introduced in the linkage process).
As mentioned earlier, factors that may significantly contribute to inconsistencies in genetic studies of osteoporosis include inadequate statistical power, population stratification, genetic heterogeneity, experimental errors, and limited coverage of genomic regions [ 27].
This shows that FDR, though important, cannot be taken at face value without the risk of losing biologically relevant information, especially in the case of STS where high FDR may result not only from heterogeneity and errors in diagnosis but also due to common pathogenic pathways resulting in similarities or overlap of expression profiles between different STS subtypes.
Using a fixed-effect model with the heterogeneity of error variance, we further illustrated that within-individual error was affected by Harvesters and ELISA operators.
Therefore, heterogeneity of error variances at different stress levels was incorporated.
A power variance function defined as Var(ε i ) = σ2|υ i |2t was specified in the model to account for the heterogeneity of error variance.
