3. A researcher in remote sensing is interested in comparing clarity (y) of 15 lakes in three different ecoregions (A, B, and C). Consider the model y = bo + biwi + baw2 + e. The first 5 rows of the data (ecolake) correspond to ecoregion A, the next 5 rows to ecoregion B, and the last 5 rows to ecoregion C. The following R output may be of use. > ecolake; w1 w2 y 1 0 0 37 IN 0 0 41 3 0 0 37 0 0 46 0 0 41 1 17 1 22 00- 0 1 23 9 0 1 22 10 0 1 19 11 1 0 56 12 1 0 52 13 1 0 48 14 1 0 41 15 1 0 54 > ecolake. Im = Im(y"w1+w2, data=ecolake) ; >summary (ecolake . 1m) ; Coefficients: Estimate Std. Error t value Pr(>It|) (Intercept) 40. 400 1.920 21. 041 7.71e-11 *** w1 9. 800 2.715 3. 609 0.00359 ** w2 -19. 800 2.715 -7. 292 9.58e-06 *** Residual standard error: 4.293 on 12 degrees of freedom Multiple R-Squared: 0.9113, Adjusted R-squared: 0.8966 F-statistic: 61.67 on 2 and 12 DF, p-value: 4.857e-07 > anova (ecolake . Im)