Table 3. Analysis of variance.

Classification Soil hardness
N Avgz (kgf/cm2) SD F p
Line 1 229 21.44b 9.64 12.07 <0.001
Line 2 295 20.20a 9.51
Groundwater line 299 22.90c 12.60
Normal site 148 26.23d 12.76
Scheffe test, a < b < c < d