Source | Value | Standard error | t | Pr > |t| | Lower bound (95%) | Upper bound (95%) |
Intercept | −12.355 | 6.805 | −1.816 | 0.073 | −25.901 | 1.190 |
Dia | −0.489 | 0.102 | −4.795 | <0.0001 | −0.692 | −0.286 |
Age | 0.008 | 0.012 | 0.725 | 0.471 | −0.015 | 0.032 |
Sand | 3.144 | 0.891 | 3.528 | 0.001 | 1.370 | 4.918 |
Clay | 0.000 | 0.000 | ||||
Low Traffic | 1.151 | 1.546 | 0.744 | 0.459 | −1.926 | 4.227 |
Heavy Traffic | 5.961 | 2.107 | 2.830 | 0.006 | 1.768 | 10.154 |
Trees | −2.819 | 1.236 | −2.280 | 0.025 | −5.280 | −0.359 |
no trees | 0.297 | 1.134 | 0.262 | 0.794 | −1.959 | 2.554 |
shallow unde 6 | 0.580 | 1.034 | 0.561 | 0.576 | −1.478 | 2.639 |
deep bury | 0.000 | 0.000 | ||||
pressure | 0.194 | 0.119 | 1.625 | 0.108 | −0.044 | 0.431 |
Ductile | 2.342 | 0.640 | 3.658 | 0.000 | 1.068 | 3.617 |
GI | 5.473 | 0.598 | 9.151 | <0.0001 | 4.282 | 6.663 |
PVC | 3.229 | 0.717 | 4.501 | <0.0001 | 1.801 | 4.657 |
AC | 12.428 | 0.757 | 16.408 | <0.0001 | 10.920 | 13.935 |
HDPE | 0.000 | 0.000 |