48 



Table 1-4. Results of regression analysis to determine the 

 of waterhyaci nths grown in barrels to treatment 

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

 b2X2 + b3(xi) 2 + b4(x2) 2 + bs(xi)(x2) where Y = 

 change in number of plants due to treatment and 

 the regression coefficients for each independent variable (X) 

 The coefficient of determination for the regression model 

 (R2) is 0.851 and the regression analysis of variance 

 F-value is 239.32 (5, 210 DF, P = 0.0001). 



response 

 with GAo and 

 bo + bixi + 

 the percent 

 b = 



Parameter 



Coefficient 



(b) 



T* 



Prob. > \ T | 



Intercept (b ) 



440.26 





35.14 



0.0001 



GA (bi) 



-1.11 





-3.70 



0.0003 



2,4-D (b2) 



-1072.92 





-22.60 



0.0001 



(GA)2 (b 3 ) 



0.0023 





1.62 



0.1070 



(2,4-D)2 (b 4 ) 



567.72 





14.61 



0.0001 



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



0.28 





1.43 



0.1549 



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



