## 3 Results
The scale distribution parameter (\(\eta\)) of the Weibull statistics showed statistically significant differences between the number of cycles to failure of the 20.06 and 25.06 apical diameter study groups (\(p<0.001\)), 20.06 and 30.06 apical diameter study groups (\(p<0.001\)), and 25.06 and 30.06 apical diameter study groups (\(p<0.001\)). In addition, the shape distribution parameter (\(\beta\)) of the Weibull statistics showed statistically significant differences between the time to failure of the 20.06 and 25.06 apical diameter study groups (\(p<0.001\)) and 20.06 and 30.06 apical diameter study groups (\(p=0.002\)); however, it did not show statistically significant differences between the time to failure of the 25.06 and 30.06 apical diameter study groups (\(p=0.644\)) (Table 4, Figure 8A). The scale distribution parameter (\(\eta\)) of the Weibull statistics showed statistically significant differences between the number of cycles to failure of 25.02 and 25.04 taper study groups (\(p<0.001\)), 25.02 and 25.06 taper study groups (\(p<0.001\)), and 25.04 and 25.06 taper study groups (\(p<0.001\)). However, the shape distribution parameter (\(\beta\)) of the Weibull statistics did not show statistically significant differences between the number of cycles to failure of the 25.02 and 25.04 taper study groups (\(p=0.144\)), 25.02 and 25.06 taper study groups (\(p=0.279\)), and 25.04 and 25.06 taper study groups (\(p=0.075\)) (Table 4, Figure 8B). \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline  & \multicolumn{4}{c}{**Weibull Shape (\(\beta\))**} & \multicolumn{4}{c}{**Weibull Scale (\(\eta\))**} \\ \hline  & **Estimate** & **St Error** & **Lower** & **Upper** & **Estimate** & **St Error** & **Lower** & **Upper** \\ \hline
20.06 & 26.24 & 6.76 & 15.84 & 43.47 & 3081.29 & 39.11 & 3005.58 & 3158.91 \\
25.02 & 37.01 & 9.07 & 22.89 & 59.85 & 3469.64 & 31.38 & 3408.68 & 3531.68 \\
25.04 & 32.46 & 7.99 & 20.03 & 52.58 & 2492.67 & 25.73 & 2442.74 & 2543.61 \\
25.06 & 22.25 & 5.51 & 13.07 & 36.14 & 1925.63 & 28.99 & 1869.64 & 1983.29 \\
30.06 & 7.62 & 1.84 & 4.74 & 12.24 & 911.45 & 40.08 & 836.17 & 993.49 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: The Weibull statistics of the number of cycles to failure for the apical diameter and taper study groups. Figure 7: Box plots of the number of cycles to failure for the (**A**) apical diameter and (**B**) taper study groups. The horizontal line in each box represents the median value. The mean and SD values for the number of cycles of in-and-out movements regarding the apical diameter and taper are displayed in Table 5 and Figure 9A,B. The ANOVA test showed statistically significant differences between the number of cycles of in-and-out movements of the apical diameter (\(p<0.001\)) (Figure 9A) and taper (\(p<0.001\)) (Figure 9B) of the NiTi endodontic rotary files. Figure 8: The Weibull probability plots of the number of cycles to failure for the (**A**) apical diameter and (**B**) taper study groups. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Study Group** & \(n\) & **Mean** & **SD** & **Minimum** & **Maximum** \\ \hline
20.06 & 10 & 361.91 & 18.07 & 328.18 & 382.91 \\
25.02 & 10 & 410.39 & 13.11 & 387.28 & 428.19 \\
25.04 & 10 & 294.27 & 10.50 & 279.87 & 310.33 \\
25.06 & 10 & 225.77 & 11.73 & 210.79 & 241.83 \\
30.06 & 10 & 102.91 & 15.41 & 81.29 & 127.91 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Descriptive statistics of the number of cycles of in-and-out movements in relation to the apical diameter and taper study groups. Figure 9: Box plots of the number of cycles of in-and-out movements for the (**A**) apical diameter and (**B**) taper study groups. The horizontal line in each box represents the respective median value.