## 5 Results
### Analysis of Rope in the Fourth Quality Class  
As shown in Table 2, the majority of wire strength values fall outside the nominal accuracy interval of \(\langle\)1770; 1911.6\(\rangle\) MPa. The target value of the nominal accuracy of the rope is 1839 MPa. From Table 2, it is possible to see significant differences in the average values of the nominal accuracy for wires No. 2, No. 3, and No. 5. The average values for these wires are significantly higher than the specified target accuracy value, namely 1839 MPa. The highest variation range is observed in wire No. 2 (V\({}_{\rm x}\) = 338.76), which is also accompanied by a relatively high standard deviation (s = 67.02). Similarly, wire No. 4 exhibits a considerable variation range (V\({}_{\rm x}\) = 285.35) and an even higher standard deviation (s = 103.70). The notably elevated variance (s\({}^{2}\) = 10 754.72) for wire No. 4 reflects substantial fluctuations in the measured strength values. From the perspective of mechanical performance, it can be concluded that the majority of measured values lie outside the nominal strength tolerance for the fourth-quality-class rope type (25 6x31 WS SFC 1770 B sZ). The shape of the constructed histogram, as shown in Figure 4, clearly contradicts the assumption of normality. Most of the measured values fall within the interval \(\langle\)1725; 1775\(\rangle\). The test data obtained from the respective steel wires, together with the specified limits--namely the lower specification limit (LSL) = 1770 and the upper specification limit (USL) = 1911.6--demonstrate that a substantial portion of the values lie outside these boundaries. Specifically, a significant number of values fall both below the LSL and above the USL, indicating a lack of process control. The target value (1839), which lies within the \(\pm 4\%\) tolerance interval, is not adequately represented in the measured data. Only 6 values fall within the interval \(\left\langle 1775;\ 1825\right\rangle,\) while 13 values are observed in the range \(\left\langle 1825;\ 1875\right\rangle.\) This highlights a clear issue with process centering, as the distribution of values is skewed and fails to align with the defined specification limits. The control chart depicted in Figure 5 reveals that the measured values fall outside the bounds of the specified nominal accuracy interval \(\left\langle 1770;\ 1911.6\right\rangle.\) This deviation indicates that the process does not conform to the established quality requirements. Furthermore, since the assumption of normal distribution is not satisfied, the calculation of capability indices is not recommended, as it may lead to erroneous conclusions. It can thus be concluded that the process is neither statistically stable nor capable. The capability analysis results presented in Figure 6 further support this finding. Due to the failure to meet the assumption of normality, capability indices were not considered valid and are excluded from further evaluation. \begin{table}
\begin{tabular}{c c c c c c} \hline  & **Wire 1** & **Wire 2** & **Wire 3** & **Wire 4** & **Wire 5** \\ \hline Mean [MPa] & 1746.41 & 1919.26 & 1941.51 & 1814.01 & 2008.82 \\ Maximum value [MPa] & 1786.43 & 2201.95 & 1981.60 & 1899.62 & 2027.66 \\ Minimum value [MPa] & 1657.05 & 1863.19 & 1804.67 & 1614.27 & 1997.51 \\ Variation range (V\({}_{\rm x}\)) [MPa] & 129.38 & 338.76 & 176.93 & 285.35 & 1230.15 \\ Standard deviation (s) [MPa] & 20.53 & 67.02 & 48.34 & 103.70 & 1313.27 \\ Variance (s\({}^{2}\)) [MPa] & 421.60 & 4491.17 & 2336.54 & 10,754.72 & 176.14 \\ \hline \end{tabular}
\end{table} 
Table 2: Statistical analysis of the strength of three wires from fourth-quality-class rope. Figure 4: Histogram and capability analysis of wire strength in a fourth-quality-class rope (5 wires). From the perspective of capability assessment, the evaluated rope must be deemed unsuitable and unfit for use.