## 4 Results  
Following the assumptions given in Section 3.1, the observed efficiencies were ordered into interval series with respect to the type of element. The results of this operation are presented in the following Tables 4-6. It is noteworthy that the number of intervals k for each type of element was assessed using the following equation:  
\[k=1+3.3\log m \tag{13}\]  
where \(m\) stands for the number of observations presented in Table 1. The ranges of the intervals resulted from an even division of efficiency value ranges by \(k\) (with the lower and upper ends rounded down and up, respectively). Table 4 shows that for column formworks, the observed values were grouped into six intervals, with a range of 0.3 for each interval. In the case of wall formwork assembly efficiencies, the observed values were grouped into seven intervals, as shown in Table 5. The range of each interval was 0.37. Table 6 shows the results for slab formworks, where the observed assembly efficiencies were also grouped into seven intervals. The range of intervals was 0.43. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Intervals’ Ranges** & **Middle of the Interval** & **Number of** & **Accumulated** & & \\
**[m2/Hour]** & **[m2/Hour]** & **Observations** & **Number of** & **Share [\%]** & **Accumulated Share [\%]** \\ \hline
0.10 \(\div\) 0.40 & 0.25 & 2 & 2 & 5.405 & 5.405 \\
0.40 \(\div\) 0.70 & 0.55 & 2 & 4 & 5.406 & 10.811 \\
0.70 \(\div\) 1.00 & 0.85 & 5 & 9 & 13.513 & 24.324 \\
1.00 \(\div\) 1.30 & 1.15 & 6 & 15 & 16.216 & 40.540 \\
1.30 \(\div\) 0.60 & 1.45 & 16 & 31 & 43.243 & 83.783 \\
1.60 \(\div\) 1.90 & 1.75 & 6 & 37 & 16.217 & 100.000 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Interval series based on observed efficiencies for column formworks assembly works. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Element** & **Min** & **Mean** & **Max** & **Median** & **Standard Deviation** \\ \hline COLUMN & 0.19 & 1.250 & 1.81 & 1.360 & 0.402 \\ WALL & 0.80 & 1.869 & 3.18 & 1.880 & 0.615 \\ SLAB & 0.28 & 1.728 & 3.14 & 1.901 & 0.721 \\ \hline \hline \end{tabular} \({}^{\ddagger}\) All values for descriptive statistics are given as [m2/hour].  
\end{table} 
Table 3: Descriptive statistics for observed values of efficiency \({}^{\ddagger}\). In the next step, triangular distributions were fitted to the observed efficiencies. Table 7 presents the minimum value \(a\), the peak value \(m\) and the maximum peak \(b\) values. Moreover, based on Equations (2)-(4), the expected value \(E(X)\), median \(Me\) and standard deviation \(\sigma\) were computed for the fitted distributions and presented in the table as well. The fitted distributions are visually depicted in Figures 2-4, where the horizontal axes represent the efficiency of column, wall, and slab formwork assembly, respectively, given in [m\({}^{2}\)/hour] (compare with Equation (12) and Tables 4-7). The vertical axes indicate the values of the probability density function \(f(x)\), computed using Equation (1) and the parameters \(a\), \(m\), and \(b\) from Table 7.  
With the knowledge of the probabilities, it was also possible to assess the duration of work or total quantity (output). This was performed on the basis of Equations (11) and (12) or their simple transformations. The results of these exemplary calculations are also presented in Table 8.  
Figure 4: Triangular distribution fitted for slab formwork assembly efficiency. Figure 3: Triangular distribution fitted for wall formwork assembly efficiency. Figure 2: Triangular distribution fitted for column formwork assembly efficiency. The computations, which results are presented in Table 8, were performed based on hypothetical critical efficiencies, \(x_{c}\), and a given number of workers. Either duration or total quantity had to be assumed in order to compute the other. Similar computations can be carried out for any reasonable and justifiable assumptions about the combination of values describing the number of workers, planned quantity of work, or duration of the task.