# Detecting Atypical Values and Their Influence on Blast-Induced Seismic Measurement Results
## 4 Discussion  
Figures 3 and 4 along with Tables 2 and 5 present the atypical values' detection process of blast-induced seismic effects measurement data. It is visible that only the confidence intervals of 0.6827 and 0.9545 (Sigma 1 and 2) detect atypical values (outliers). The other two confidence intervals of 0.9973 and 0.9999 (Sigma 3 and 4) do not detect any measurement point as an atypical value. Therefore, only the first two were used for further analyses. It also shows that a confidence interval of 0.6827 excludes about half or more measurement points from one measurement dataset, while a confidence interval of 0.9545 excludes only one or two points. Regression lines with 95%-line equations, coefficients of determination (R\({}^{2}\)) and standard deviations are presented in Figure 5 and Tables 3 and 6. It is observable that the 95%-line equations are different depending on how many measurement points were excluded during the detection of atypical values. Mainly the coefficient of determination (R\({}^{2}\)) is closest to the value of 1 when atypical values are excluded using a confidence interval of 0.6827 compared to a confidence interval of 0.9575 or the full measurement dataset. This is because, when using the confidence interval of 0.6827, about half or more measurement points were excluded; therefore, only measurement points closest to the mean remained. However, the coefficient of determination for the equations using the confidence interval of 0.9575 is not far behind. When looking at the standard deviation for the mentioned cases, the results are similar. When using the confidence interval of 0.6827, the standard deviation is closest to zero, as expected, followed by a confidence interval of 0.9575 and the further away from zero is again the full measurement dataset. Additionally, boreholes B2, B3, B4, B7, B8 and B17, while using a confidence interval of 0.6827, do not provide any result for the regression lines with 95%-line equations, coefficients of determination and standard deviations due to not having the minimum of four monitoring points required for the application \"Blastware\" to perform further analyses. \begin{table}
\begin{tabular}{c c c} \hline \hline \multirow{2}{*}{**Borehole**} & \multicolumn{2}{c}{**Ratio**} \\ \cline{2-3}  & **68.27/100** & **95.45/100** \\ \hline B1 & 1.59 & 1.53 \\ \hline B2 & / & 1.59 \\ \hline B3 & / & 10.93 \\ \hline B4 & / & 2.83 \\ \hline B5 & 6.63 & 7.99 \\ \hline B6 & 1.20 & 1.20 \\ \hline B7 & / & 1.08 \\ \hline B8 & / & 1.00 \\ \hline B9 & 1.03 & 1.00 \\ \hline B10 & 7.94 & 0.66 \\ \hline B11 & 1.40 & 0.85 \\ \hline B12 & 3.17 & 2.17 \\ \hline B13 & 4.96 & 5.58 \\ \hline B14 & 4.21 & 4.54 \\ \hline B15 & 1.37 & 0.95 \\ \hline B16 & 3.06 & 0.81 \\ \hline B17 & / & 1.00 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Ratio between both confidence intervals (68.27% and 95.45%) and the full dataset for all 17 blast holes. The final and most important calculation for blasting contractors is the permitted charge weight per delay for the required distances from the blasting zone, with selected maximum PPV according to the type of the surrounding structures. Figure 5 and Tables 4 and 7 provide an insight into how different these values can depend on how many monitoring points are excluded during the atypical value detection process. It can be observed that, at boreholes B2, B3, B4, B7, B8 and B17, while using a confidence interval of 0.6827, there are less than the minimum four measurement points required for the application to calculate the regression lines with 95%-line equations, coefficients of determination and standard deviations as well as the permissible charge weight per delay. The remaining results obtained using a confidence interval of 0.6827 provide lenient results, i.e., causes an increase in the permissible charge weight per delay comparing to the full measurement dataset, maintaining the safety level identical, which in the end provides more cost-efficient blasting works.