Optimization of River Sand with Spent Garnet Sand in Concrete Using RSM and R Programming Packages

Table 4

ANOVA response 1: compressive strength at 28 days (RStudio).

	Estimate	Std. error	value		Remarks
(Intercept)	2.027e+01	4.848e-01	41.822	1.46e-12	Significant
A	7.098e-02	3.699e-03	19.187	3.22e-09	Significant
B	NA	NA	NA	NA	Insignificant
AB	1.701e-03	2.126e-04	7.999	1.18e-05	Significant