An experiment to evaluate the effects of certain variables on soil erosion was performed on 10-foot-square plots of sloped farmland subjected to 2 inches of artificial rain applied over a 20-minute period. The data and related ANOVA table are as follows:

a. Compute R2, and comment on the fit of the model.
b. The fitted model involving all three independent variables is given by Ŷ = -1.879 + 77.326X1 + 1.559X2 - 23.904X3. Compute and compare observed and predicted values of Y for plots 1, 5, and 7.

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Plot 8 10 SL(Y) SG(%) LOBS (X) 27.1 35.6 1.4 378 402 39.855.5 43.6 52.1 43.8 5 0.43 0.47 0.44 0.48 0.48 0.49 0.53 5 055 05 0.48 1.95 5.13 398 6.25 7.12 6.50 10.67 7.08 9.88 87 496 0.34 0.32 0.29 0.30 0.25 0.26 0.10 016 0.19 018 0.28 Source d.f Regression Residual 680.4912 16.0942 7 Total 10 696.5855