47 



response 

 with GA 3 and 

 bo + t>ixi + 

 the percent 



Table 1-3. Results of regression analysis to determine the 

 of waterhyacinths grown in barrels to treatment 

 2,4-D. The general form of the equation is Y = 



D2X2 + b 3( x l) 2 + b 4( x 2) 2 + b5(xi)(x2) where Y = 

 change in biomass due to treatment and b = the 

 regression coefficients for each independent variable (X). 

 The coefficient of determination for the regression model 

 (R 2 ) is 0.829 and the regression analysis of variance 

 F-value is 203.65 (5, 210 DF, P = 0.0001). 



Parameter 



Coefficient 



(b) 



T* 



Prob. > \ T \ 



Intercept (b ) 



230.91 





26.16 



0.0001 



GA (bi) 



-0.39 





-1.84 



0.0675 



2,4-D (b2) 



-739.96 





-22.12 



0.0001 



(GA) 2 (b 3) 



0.0002 





0.24 



0.8135 



(2,4-D)2(b4) 



414.54 





15.13 



0.0001 



(GA)x(2,4-D) (b 5 ) 



0.13 





0.91 



0.3663 



*T-statistics for the null hypothesis that the coefficient = 0. 



