# Waste Reduction Methods Used in Construction Companies with Regards to Selected Building Products
## 4 Results
In turn, Figure 6b shows a diagram illustrating the frequency of using the \"Timely delivery\" method in companies of various sizes. In this case, the height of the bars does not show an unequivocal growing trend of used methods along with the size of companies. However, a much higher frequency of using this method can be noticed in companies of all sizes for wood products when compared to other product groups. Table 4 presents the methods of waste reduction for five examined groups of building products for which the frequency of use depends on the size of a company. \begin{table}
\begin{tabular}{p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt} p{42.7 pt}} \hline \hline \multirow{2}{*}{**No.**} & \multicolumn{2}{c}{**Methods of Reducing the**} & \multicolumn{4}{c}{**Building Material**} \\ \cline{3-8}  & \multicolumn{1}{c}{**Amount of Construction**} & \multicolumn{1}{c}{**Steel**} & \multicolumn{1}{c}{**Concrete**} & \multicolumn{1}{c}{**Masonry Products**} & \multicolumn{1}{c}{**Ceramic and Stone Tiles**} & \multicolumn{1}{c}{**Wood**} \\ \hline
1 & Adequate storage & \(\chi^{2}=5.26\); \(p=0.261\) & \(\chi^{2}=5.81\); \(p=0.213\) & \(\chi^{2}=10.71\); \(p=0.03\) & \(\chi^{2}=11.43\); \(p=0.022\) & \(\chi^{2}=11.17\); \(p=0.025\) \\ \hline
2 & Ordering products as per size and in the right quantity & \(\chi^{2}=3.057\); \(p=0.548\) & \(\chi^{2}=8.186\); \(p=0.085\) & \(\chi^{2}=3.814\); \(p=0.432\) & \(\chi^{2}=2.97\); \(p=0.563\) & \(\chi^{2}=7.361\); \(p=0.118\) \\ \hline
3 & Training of employees in the field of management & \(\chi^{2}=4.188\); \(p=0.381\) & \(\chi^{2}=4.657\); \(p=0.324\) & \(\chi^{2}=9.60\); \(p=0.048\) & \(\chi^{2}=7.313\); \(p=0.12\) & \(\chi^{2}=8.028\); \(p=0.091\) \\ \hline
4 & Use of monitoring systems & \(\chi^{2}=13.751\); \(p=0.008\) & \(\chi^{2}=11.272\); \(p=0.024\) & \(\chi^{2}=13.754\); \(p=0.008\) & \(\chi^{2}=16.369\); \(p=0.003\) & \(\chi^{2}=14.996\); \(p=0.005\) \\ \hline
5 & Proper transport and storage & \(\chi^{2}=7.197\); \(p=0.126\) & \(\chi^{2}=6.023\); \(p=0.197\) & \(\chi^{2}=10.777\); \(p=0.029\) & \(\chi^{2}=8.1\); \(p=0.088\) & \(\chi^{2}=5.072\); \(p=0.28\) \\ \hline
6 & Appropriate involvement of subcontractors & \(\chi^{2}=10.671\); \(p=0.031\) & \(\chi^{2}=8.144\); \(p=0.086\) & \(\chi^{2}=17.855\); \(p=0.001\) & \(\chi^{2}=8.977\); \(p=0.062\) & \(\chi^{2}=11.495\); \(p=0.022\) \\ \hline
7 & Site security & \(\chi^{2}=1.899\); \(p=0.754\) & \(\chi^{2}=3.2;p=0.525\) & \(\chi^{2}=8.113\); \(p=0.088\) & \(\chi^{2}=3.869\); \(p=0.424\) & \(\chi^{2}=4.308\); \(p=0.366\) \\ \hline
8 & Use of prefabricated elements & \(\chi^{2}=13.259\); \(p=0.01\) & \(\chi^{2}=5.687\); \(p=0.024\) & \(\chi^{2}=12.315\); \(p=0.2315\) & \(\chi^{2}=7.825\); \(p=2.693\); \(p=0.015\) & \(\chi^{2}=2.693\); \(p=0.011\) \\ \hline
9 & Waste segregation on site & \(\chi^{2}=4.546\); \(p=0.337\) & \(\chi^{2}=1.702\); \(p=0.79\) & \(\chi^{2}=3.525\); \(p=0.474\) & \(\chi^{2}=2.385\); \(p=0.665\) & \(\chi^{2}=5.971\); \(p=0.201\) \\ \hline
10 & Designation of a place for waste segregation & \(\chi^{2}=4.299\); \(p=0.367\) & \(\chi^{2}=1.005\); \(p=0.909\) & \(\chi^{2}=2.963\); \(p=0.564\) & \(\chi^{2}=1.655\); \(p=0.799\) & \(\chi^{2}=0.767\); \(p=0.943\) \\ \hline
11 & Reuse of products within the construction & \(\chi^{2}=6.871\); \(p=0.143\) & \(\chi^{2}=9.862\); \(p=0.043\) & \(\chi^{2}=14.825\); \(p=0.005\) & \(\chi^{2}=11.056\); \(p=0.026\) & \(\chi^{2}=13.027\); \(p=0.011\) \\ \hline
12 & Timely delivery of products & \(\chi^{2}=5.707\); \(p=0.222\) & \(\chi^{2}=1.682\); \(p=0.794\) & \(\chi^{2}=5.063\); \(p=0.281\) & \(\chi^{2}=4.082\); \(p=0.395\) & \(\chi^{2}=2.284\); \(p=0.684\) \\ \hline
13 & Having a waste management plan & \(\chi^{2}=5.211\); \(p=0.266\) & \(\chi^{2}=2.346\); \(p=0.672\) & \(\chi^{2}=2.631\); \(p=0.621\) & \(\chi^{2}=1.733\); \(p=0.785\) & \(\chi^{2}=2.937\); \(p=0.568\) \\ \hline \hline \end{tabular}  
Statistically significant results marked in gray.  
\end{table} 
Table 3: Chi-square test statistics.