Fig. 4

Equivalence plots of observed vs. predicted AGC by the LOOCV5 and LOOCV10 (a, b); (n = 136). The equivalence plot design presented herein is an adaptation of the original equivalence plots presented by [52]. The grey polygon represents the ±25% region of equivalence for the intercept, and the red vertical bar represents a 95% of confidence interval for the intercept. The predicted AGC from the LOOCV5 and LOOCV10 models are equivalents to the reference for the intercept if the red bar is completely within the grey polygon. If the grey polygon is lower than the red vertical bar, the predicted AGC is biased low; and if it is higher than the red vertical bar, the predicted AGC is biased high. Moreover, the grey dashed line represents the ±25% region of equivalence for the slope, and if the green vertical bar is contained completely within the grey dashed line, the pairwise measurements are equal. Red and green bars are wider than the region outlined by the grey dashed lines indicates highly variability predictions. The white dots are the pairwise measurements, and the solid line is a best-fit linear model for the pairwise measurements. The light grey dashed line represented the relationship 1:1