# Effect of Augmented Reality Support on Quality Inspection of Welded Structures
## 4 Results
### Mental Workload  
Another area monitored in the experiment was mental workload. The NASA standardised Task Load Index (TLX) questionnaire was used to assess the mental load of the participants during the experiment. This questionnaire is used to measure perceived mental workload and is often used in research involving human factors and ergonomics.  
To understand the nature of the data collected, a graphical analysis of the average level of perceived mental workload and standard errors was performed (Figure 10). This analysis allows for a visual comparison of the average mental workload values between the groups, while also providing information on the variance of the data within each group. The figure illustrates the perceived mental workload components assessed using the NASA Task Load Index method. The y-axis represents the subjective ratings for different workload components. NASA TLX scores are not expressed in specific physical units, but rather reflect participants' subjective assessments of workload, effort, and frustration. The graph is used to visually compare and analyse the relative differences in perceived workload between different tasks or conditions, providing insight into the cognitive and perceptual aspects of task demands.  
Figure 10: Mental workload of the participants.  
Figure 9: Average number of errors.  
The graph shows that the lowest mean value of perceived mental workload was achieved in G1 using the AR approach. The second lowest value was perceived in G2 when using the AR approach. This analysis provides valuable information on the differences in perceived mental workload between users depending on the inspection approach chosen and the level of experience. The results suggest that the AR approach may yield a reduction in perceived mental workload among users compared to the conventional approach. The conventional approach shows significantly higher levels of mental workload in most of the areas examined compared to the AR approach. The highest levels were observed using the conventional approach in the areas of mental demand and effort. These areas also showed the highest differences compared to the AR approach. The performance indicator showed the smallest difference between the two approaches.  
The results of the two-way analysis of variance (ANOVA) indicated statistically significant differences in perceived mental workload between the different combinations of experience factors and the approach used. Within G1, it was found that the use of the AR approach had a mean mental workload of 60.25, whereas the use of the conventional method had a mean value of 149.75. The overall mean for the G1 group was 105. On the other hand, in G2, it was found that the AR methodology had an average mental workload value of 106.25, while the conventional method had an average value of 181.5. The overall mean for group G2 was 143.88.  
The F-value for the approach comparison was 25.20, which is significantly higher than the critical value of Fcrit = 3.97. The \(p\)-value, on the other hand, is very low and is therefore statistically significant, indicating that there is a significant difference in perceived mental workload between the AR approach and the conventional approach.  
Overall, the results can be interpreted to indicate that the use of the conventional methodology shows a significantly higher mental workload compared to the AR approach. The highest values were observed for time and effort when using the conventional method. The smallest differences were observed in performance. These data support the conclusion that the AR methodology may provide benefits in reducing perceived mental workload compared to the conventional methodology. These findings have implications for the further development and investigation of interactive systems, and can serve as a basis for the design of user interfaces concerning user mental workload.