## 3 Results and Discussion
### Descriptive Statistics
#### 3.2.1 CoM Descriptive Statistics  
Descriptive one-dimensional statistics of position and variability CoM of Arm I--AdM and Arm I--CvM are in Table 7. As follows from the CoM principle (Section 2.3), the results in Table 7 are given in mm. It is clear from Table 7 that the mean values of measurements do not have the same value. Maximum variability for expression is the standard deviation (sd) of 0.20 mm. Another indicator of variability is the range. The skewness indicator describes the skewing of selections. In cases of measurements in the direction of the Y axis, when the hypothesis of a normal distribution of sets was rejected, high values of this indicator can be observed. The kurtosis indicator should be approximately 0. Negative values less than -1 indicate \begin{table}
\begin{tabular}{c c c} \hline \hline \multicolumn{1}{c}{**Statistics**} \\ \cline{2-3}
**Measurement** & **Shapiro-Wilk** & **Kolmogorov-Smirnov/** **Pearson Chi-Square** & **Normal Distribution** \\ \hline AdM\_NcM\_0\_X & W = 0.85477, \(p\)-value = 0.04924 & D = 0.21081, \(p\)-value = 0.1872 & not reject \\ AdM\_NcM\_0\_Y & W = 0.93381, \(p\)-value = 0.4506 & & not reject \\ AdM\_NcM\_0\_Z & W = 0.93928, \(p\)-value = 0.5121 & & not reject \\ AdM\_NcM\_1\_X & W = 0.95168, \(p\)-value = 0.6655 & & not reject \\ AdM\_NcM\_1\_Y & W = 0.93625, \(p\)-value = 0.4775 & & not reject \\ AdM\_NcM\_1\_\_Z & W = 0.92879, \(p\)-value = 0.3988 & & not reject \\ AdM\_NcM\_2\_\_X & W = 0.85927, \(p\)-value = 0.05633 & & not reject \\ AdM\_NcM\_2\_\_Y & W = 0.90404, \(p\)-value = 0.2069 & & not reject \\ AdM\_NcM\_2\_\_Z & W = 0.9122, \(p\)-value = 0.2589 & & not reject \\ CvM\_NcM\_0\_\_X & W = 0.9326, \(p\)-value = 0.4377 & & not reject \\ CvM\_NcM\_0\_\_Y & W = 0.88651, \(p\)-value = 0.1257 & & not reject \\ CvM\_NcM\_0\_\_Z & W = 0.86383, \(p\)-value = 0.06454 & & not reject \\ CvM\_NcM\_1\_\_X & W = 0.97466, \(p\)-value = 0.9293 & & not reject \\ CvM\_NcM\_1\_\_Y & W = 0.72731, \(p\)-value = 0.001054 & D = 0.26732, \(p\)-value = 0.06298 & not reject \\ CvM\_NcM\_1\_\_Z & W = 0.92219, \(p\)-value = 0.3373 & & not reject \\ CvM\_NcM\_2\_\_X & W = 0.8197, \(p\)-value = 0.02513 & D = 0.24475, \(p\)-value = 0.09133 & not reject \\ CvM\_NcM\_2\_\_Y & W = 0.98184, \(p\)-value = 0.9755 & & not reject \\ CvM\_NcM\_2\_Z & W = 0.85555, \(p\)-value = 0.05041 & & not reject \\ \hline \hline \end{tabular}
\end{table} 
Table 6: NcM normality test. that the frequency distribution curve is too flat. Positive values indicate that the point density is too high. The minimum, maximum and median are shown by the box graphs in Figures 13-15. For measurements in the direction of the X axis (Figure 13), for Arm I--AdM and Arm I--CvM, a significant decrease in the median position of the arm showed when changing the load from 0 kg to 1 kg and a slight decrease in median position is still visible when changing the load from 1 kg to 2 kg. The variability of measurements in the direction of the X axis evaluated by range and standard deviation sd is highest for the measurement AdM_CoM_1_Xx. With both types of arm, the robot arm decreases in the X-axis direction as the load increases. For the measurement in the direction of the Y axis (Figure 14), for Arm I--AdM, there is a significant increase in the median position when changing the load from 0 kg to 1 kg and a slight decrease in the median position when changing the load from 1 kg to 2 kg. Arm I--CvM shows a significant decrease in the median position when changing the load