4.3.5. Normality of the error distribution
The assumption of normality of the error distribution has been statistically tested by applying Kolmogorov–Smirnov (K–S) test. In both cases (OGP and FOM), K–S with Lilliefors correction test has P N 0.05 which indicates normal distribution of residuals (K–SOGP = 0.043, P = 0.20; K-SFOM = 0.063, P = 0.20).