The Development of a Mathematical Model for the Prediction of Corrosion Rate Behaviour for Mild Steel in 0.5 M Sulphuric Acid

Table 8

Effect of the variables at 95% confidence level for Grewia venusta extract.

Factor	Coefficient estimate	Degree of freedom	Standard error	95% CI low	95% CI high
Intercept	40.52	1	1.20	35.58	45.66
Temperature (A); 1.00	6.40	1	1.20	1.26	11.54
Inhibitor (𝐵); 1.00	−20.03	1	1.20	−25.17	−14.89
Time (𝐶); 1.00	−9.47	1	1.20	−14.61	−4.33
AB; 1.00	−2.51	1	1.20	−7.65	2.63
BC; 1.00	−2.54	1	1.20	−7.68	2.60