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. 2013 Jan 8;1(1):45–53. doi: 10.1002/fsn3.7

Table 3.

Determination coefficient of calibration (R2) and mean global-H values for two different near-infrared reflectance spectroscopy calibration models developed for crude protein content (CP, in%) using different sets of cowpea leaf samples available for this study

Initial model New model
Sample sets N R2 Global-H R2 Global-H
Overall 561 0.82 3.46 0.93 0.71
Location
 Arusha, Tanzania 173 0.92 2.58 0.95 0.58
 Dodoma, Tanzania 39 0.53 6.42 0.53 0.87
 Majimoto, Tanzania 39 0.70 3.22 0.82 0.67
 Morogoro, Tanzania 36 0.78 3.66 0.84 0.62
 Mwanga, Tanzania 66 0.86 2.82 0.91 0.71
 Serere, Uganda 31 0.78 2.97 0.85 0.51
Markets/farmers
 Markets, Kenya and Tanzania 93 0.94 4.36 0.95 1.02
 Farmers, Tanzania 84 0.70 3.52 0.70 0.76

N, number of samples (included 167 samples from the initial calibration model); R2, determination coefficient of calibration; G-H, global-H value, where H is the Mahalanobis distance.