Table 5: Variance analysis of the polynomial model of first order for the dairy wastewater treatment by photocatalyst treatment. 

 Coefficient  SE coefficient  T  P 
 Constant  8.852  8.558  1.02  0.382  Reaction time  3.765  2.850  1.32  0.278  Thickness of ZnO  1.835  2.850  0.64  0.565  pH  −4.600  2.850  −1.61  0.205  Effluent concentration  −0.260  2.850  −0.09  0.933 


S = 4.03031, = 61.4%, (adjusted) = 10.0%.
