## 4 Results and Discussion
### Tiling Works  
In relation to the statistical analyses of the construction processes related to installing interior floor and wall tiles, the corresponding values of the time norms were applied according to the database. The time norm for interior wall tiles amounts to 1.41 Nh/m\({}^{2}\), while this value for the interior floor tiles amounts to 1.23 Nh/m\({}^{2}\). The calculated labor production value per worker per shift for interior wall tiles is 5.7 m\({}^{2}\)/shift, while for interior floor tiles, this number is 6.5 m\({}^{2}\)/shift. In order to simplify the calculations, we will only use one average value of 6.3 m\({}^{2}\)/shift. This number takes into account the mutual ratio of the implemented surfaces of the interior wall and floor tiles (1:4). To implement this process, a total of 20 workers were employed.  
SO J34  
* Estimated range of mean value u  
Considering the number of employed workers, only a small number of random tests are available (\(\leq\)30). The performance per work cycle, which represents one shift, will be recorded.  
Because of the number of tile workers (10) working at each building structure of SO J34 and SO J12, data will be collected from 15 random tests in the form of a workers'  
Figure 10: Graphic illustration of the plaster works performances including the mean value.  
performances per shift--as shown in Table 7. Mathematical formulas (1)-(4) will be used for the calculation of the mean value range of plastering works' performance. The estimated range interval of the mean value \(\upmu\) will be calculated for each structure separately, because the tiling works at SO J34 and SO J12 will take place simultaneously. It is thus expected that the achieved performances per shift will be different for each of the structures.  
Conclusion: The calculation demonstrated that the worker's productivity interval falls between 5.14 m\({}^{2}\) and 5.26 m\({}^{2}\)/shift. Compared to the planned value stated in database, the center of the range is 17.5% lower--as shown in Figure 11. The achieved labor productivity at SO J12 is 3.5% lower than that at SO J34, where the range of the performance mean value is between 4.95 m\({}^{2}\) and 5.05 m\({}^{2}\) of the tiled interior wall and floor tiles.  
* Relative frequency  
The objective of the relative frequency test is to assess the fulfillment of the estimated range interval of the mean value during one work cycle (two shifts), for which the fulfillment of the bottom performance limit will be marked as a successful test (U), while not fulfilling the limit will be considered an unsuccessful test (N). The relative frequency test will be executed for both structures, SO J34 as well as SO J12. The relative frequency test is supposed to verify the stability of the fulfillment of the range of mean value \(\upmu\) for a certain time. Mathematical Formula (7) will be used for the calculation.  
Conclusion: The relative frequency test of the fulfillment of the mean value with a 95% reliability for a period of one work cycle (two shifts) ranges between 82.4% and 105.5% with the stipulation that the center of this range amounts to 93.9%. Compared to SO J34, the relative frequency of the fulfillment of the range of the labor productivity mean value of the tiling works at SO J12 is lower and ranges between 79.3% and 100.7% with a range center at 90%. This value is lower by 3.9%. The execution of the hypothesis test of relative frequency shown in Section 3.2.6 did not require any personal measure to secure the commencement of the subsequent construction process.