experimental results and predicted models which ranged
from between –18.613 and 17.7697, percentage (%) error
from -0.122620038 and 0.11606597, -21.2792 and
24.7827, percentage (%) error from -0.126307491 and
0.215127604 and -102.703 and 63.4651, percentage (%)
of -0.603425382 and 0.372951166. The results of residual
analyses and percentage (%) errors for ridging operations
at all the tillage speeds showed no significance
differences.