Variability was calculated as coefficient of variation (CV).
The 18F-FDG study was performed twice using two independent batches of animals, referred to as study 1 and study 2. Variability of tracer uptake to the brain (18F-FDG) or striatum (18F-fallypride) was calculated as coefficient of variation (COV), corresponding to the relative standard deviation of the mean.
The detection limit (10 mg/l) and quantitation limit (50 mg/l) were identical for mannitol, xylose, sucrose and lactulose, and reproducibility calculated as coefficient of variation was consistently below 7%.
Temporal variability in abundance was calculated as coefficients of variation (CV; standard deviation/mean), which standardize for differences in abundance [5].
Imprecision (error) attributable to purely analytical variation was calculated as coefficients of variation on molar values from triplicate LC-MS injections of the same sample, taken over the 10 to 90% percentile of dynamic range of quantification, i.e. excluding 10% lowest or highest abundances.
The ICC (intraclass correlation coefficient) was calculated, as well as the coefficient of repeatability and the coefficient of variation.
The coefficients of ileal apparent digestibility (CIAD) for DM, GE, CP, and AA were calculated as were the coefficients of total tract apparent digestibility (CTTAD) of DM and GE.
The ratio between inspiratory and total time (Ti/Ttot) was calculated, as well as the coefficients of variation of V T, RR, and Ti/Ttot.
To determine whether we are in the presence of absolute beta convergence towards a common steady state or conditional beta convergence towards country-specific steady states, we need to test for the presence of sigma convergence, calculated as the coefficient of variation of social expenditure growth.
For repeatability (intra-device), the mean absolute difference was calculated, as was the Bland-Altman coefficient of repeatability (expressed in % of the mean thickness).
How well the total (T) thyroid interpolated the L and R MRT values was calculated as a coefficient of variation of interpolation, CV interpolation), from the standard deviation of the distances to interpolation, d = MRTTotal − min{MRTL, MRTR}, divided by the mean of their interpolation interval, ii = |MRTL − MRTR|.
