## 3 Results
### Results of Statistical Analysis for the NiTi-2 Alloy  
The previously used set of 27 theoretical continuous distributions was additionally fitted into the empirical data relating to the monthly corrosion rate in the NiTi-2 alloys. All fitted results were validated using KS and AD tests, and ranked based on the test statistics obtained over the KS test. In this way, the three best-fitted distributions were selected for the air, tide and water environments in the case of the NiTi-2 alloy. The three best-fitted distributions with the best-performing parameters are shown in Table 11 for each observed seawater environment. The expressions in Equations (31)-(33) were formed for the three best-fitted three-parameter distributions detected for the air environment, using standard expressions describing the corresponding PDFs and substituting the calculated values of all three parameters. These formulas represent analytical forms of PDFs related to the Burr, Log-Logistic and Frechet distributions. \[f_{a_{2}}^{(b)}(x)=\frac{0.260796}{\left(1+0.623103x^{0.15416}\right)^{3.715}x^ {0.84584}},\ x\geq 0 \tag{31}\] \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Environment** & **Distribution (Parameters)** & **KS Ranking** & **AD Ranking** \\ \hline \multirow{3}{*}{Air} & Burr (0.15416, 21.51, 2.715) & 1 & 1 \\ \cline{2-4}  & Log-Logistic (2.2589, 1.1902, 2.1909) & 2 & 3 \\ \cline{2-4}  & Fréchet (0.68413, 1.4445, 2.0152) & 3 & 2 \\ \hline \multirow{3}{*}{Tide} & Log-Logistic (2.9765, 9.4705, \(-\)0.31248) & 1 & 1 \\ \cline{2-4}  & Dagum (0.80238, 3.1011, 10.229) & 2 & 2 \\ \cline{2-4}  & Gamma (2.0829, 4.4208, 1.43) & 3 & 3 \\ \hline \multirow{3}{*}{Sea} & General Pareto (\(-\)0.33758, 17.894, 10.585) & 1 & 20 \\ \cline{2-4}  & Dagum (3.16, 3.1334, 13.409) & 2 & 8 \\ \cline{1-1} \cline{2-4}  & Fatigue Life (0.48433, 19.344, 2.3488) & 3 & 2 \\ \hline \hline \end{tabular}
\end{table} 
Table 11: The three best-fitted three-parameter distributions for the NiTi-2 alloy in air, tide and sea environments. Figure 14: P-P plot comparing the fitted theoretical CDFs against the empirical CDF of corrosion rate in a sea environment related to the NiTi-1 alloy. \[f_{a_{2}}^{(l)}(x)=\frac{1.52433(x-2.1909)^{1.2589}}{\left(1+0.674811(x-2.1909)^{2. 2589}\right)^{2}},\ x\geq 2.1909, \tag{32}\]  
\[f_{a_{2}}^{(f)}(x)=\frac{0.879845e^{-\frac{1.286078}{(x-2.0152)^{0.68413}}}}{(x- 2.0152)^{1.68413}},\ x>2.0152. \tag{33}\]  
Based on the previously determined set of three parameters for each of the observed theoretical distributions for the air environment (Table 11), taking into account their PDF Equations (31)-(33), adequate CDF formulas for the best fitted Burr, Log-Logistic and Frechet distributions for the air environment were determined, as is shown in Equations (34)-(36). \[F_{a_{2}}^{(b)}(x)=1-\frac{1}{(1+0.623103x^{0.15416})^{2.715}},\ x\geq 0 \tag{34}\]  
\[F_{a_{2}}^{(l)}(x)=\frac{1}{1+1.4819\Big{(}\frac{1}{x-2.1909}\Big{)}^{2.2589} },\ x\geq 2.1909, \tag{35}\]  
\[F_{a_{2}}^{(f)}(x)=e^{-\frac{1.286078}{(x-2.0152)^{0.68413}}},\ x>2.0152. \tag{36}\]  
The mean values of the previously specified Burr, Log-Logistic, and Frechet distributions (3.8585 nm/month, 3.8734 nm/month, 3.8519 nm/month, respectively, with Standard Deviations of 1.8785 nm/month, 2.89 nm/month, 1.9212 nm/month, respectively), were taking values very close to the calculated mean value of the parameter \(c_{1}\) from Equation (5), showing the correctness of the distribution fitting approach. By applying the statistical procedure of fitting three-parameter distributions, the Log-Logistic, Dagum and Gamma distributions proved to be the three best theoretical distributions for describing empirical data of the corrosion rate caused by the tide's influence. After incorporating the best values of the three parameters, the PDFs of these three functions yielded in Equations (37)-(39).