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Table 6 Statistical model summary of citric acid and effersoda on hardness

From: Application of response surface methodology (RSM) in statistical optimization and pharmaceutical characterization of a patient compliance effervescent tablet formulation of an antiepileptic drug levetiracetam

Source of variation DF Adj sum of square Adj mean square F value P value summary
Value Significant
Model 6 2248.22 374.70 67.26 0.000 Model significant
Linear 2 292.84 146.42 26.28 0.001
Citric acid 1 236.05 236.05 42.37 0.000
Effersoda 1 56.78 56.78 10.19 0.015
Square 2 1851.88 925.94 166.20 0.000
Citric acid (mg)*citric acid (mg) 1 782.17 782.17 140.40 0.000
Effersoda*effersoda 1 1208.32 1208.32 216.89 0.000
2-way interaction 1 100.00 100.00 17.95 0.004
Citric acid (mg)*effersoda 1 100.00 100.00 17.95 0.004
Lack-of-fit 3 8.33 2.78 0.36 0.785 Lack-of-fit not significant
Model summary
S R-sq R-sq (adj) R-sq (pred)
2.36032 98.92% 96.83% 94.00%