Sorry for the technical error. The sample set was divided into two subsets (75% and 25%) for calibration (86 samples) and validation (28 samples).
When the samples are grouped, it is generally carried out according to 7:3 or 3:1 or a certain ratio. There are 114 soil samples in this study, what is the basis for grouping by 88/26 (77.2%/22.8%)?