=+44. Coir fiber, derived from coconut, is an eco-friendly material with great potential for use in construction. The article “Seepage Velocity and Piping Resistance of Coir Fiber Mixed Soils” (J. of Irrig.

and Drainage Engr., 2008: 485–492) included several multiple regression analyses. The article’s authors kindly provided the accompanying data on x1 5 fiber content (%), x2 5 fiber length (mm), x3 5 hydraulic gradient (no unit provided), and y 5 seepage velocity (cm/sec).

Obs cont lngth grad vel Obs cont lngth grad vel 1 0.0 0 0.400 0.027 26 1.5 50 1.141 0.058 2 0.0 0 0.716 0.050 27 1.5 50 1.474 0.082 3 0.0 0 0.925 0.080 28 1.5 50 1.581 0.112 4 0.0 0 1.098 0.099 29 1.5 50 1.983 0.144 5 0.0 0 1.226 0.107 30 1.0 25 0.462 0.028 6 0.0 0 1.427 0.140 31 1.0 25 0.705 0.059 7 0.0 0 1.709 0.178 32 1.0 25 0.987 0.084 8 0.0 0 1.872 0.200 33 1.0 25 1.154 0.101 9 0.5 50 0.380 0.022 34 1.0 25 1.479 0.150 10 0.5 50 0.774 0.040 35 1.0 25 1.786 0.194 11 0.5 50 1.056 0.060 36 1.0 25 1.957 0.218 12 0.5 50 1.329 0.111 37 1.0 40 0.419 0.030 13 0.5 50 1.598 0.158 38 1.0 40 0.705 0.050 14 0.5 50 1.799 0.188 39 1.0 40 0.979 0.068 15 1.0 50 0.410 0.026 40 1.0 40 1.226 0.091 16 1.0 50 0.577 0.038 41 1.0 40 1.470 0.126 17 1.0 50 0.748 0.049 42 1.0 40 1.744 0.168 18 1.0 50 0.927 0.060 43 1.0 60 0.436 0.034 19 1.0 50 1.090 0.070 44 1.0 60 0.650 0.051 20 1.0 50 1.239 0.088 45 1.0 60 0.889 0.068 21 1.0 50 1.496 0.111 46 1.0 60 1.222 0.093 22 1.0 50 1.744 0.134 47 1.0 60 1.477 0.112 23 1.0 50 1.915 0.145 48 1.0 60 1.726 0.139 24 1.5 50 0.444 0.014 49 1.0 60 1.983 0.173 25 1.5 50 0.821 0.037