## 3 Results
### Accuracy Analyses of Experimental Results
#### 3.2.1 Accuracy Analyses for All Output Data  
The system used five electrodes (T3, T4, Pz, Cz, and Fz) to gain the potential data of the participants' brainwaves (ERPs). The system also outputs the classification results from the EEG data of five electrodes based on each component of the ERPs (Tables 2-4). Additionally, Figure 8 shows the potential difference between target and non-target.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline  & & & & & & **Unit: \%** \\ \hline
**Subjects** & **T3** & **T4** & **Fz** & **Cz** & **Pz** & **Average** \\ \hline N01 & 50.00 & 50.00 & 70.00 \({}^{\star}\) & 60.00 & 45.00 & 55.00 \\ N02 & 60.00 & 65.00 & 75.00 & 80.00 \({}^{\star}  
Component N2P3 was used to analyze the output of the EEG online. The experimental results in Tables 2-4 demonstrate the correctness of the system's experimental setup: the N2P3 features enabled the best discrimination. Table 5 displays the paired samples t-test results between the target and non-target options regarding accuracy and potential. These results indicate that component N2P3 can discriminate the features of ERPs well. Thus, component N2P3 is the optimal ERP for interpretation.  
Figure 8: The potential differences between the target and non-target using components N200, P300, and N2P3 of ERPs to classify data from the five electrodes.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & & & \multicolumn{2}{c}{\(\boldsymbol{\alpha}\) = 0.01, N = 480} & & & \\ \hline \multirow{4}{*}{**Components**} & \multirow{2}{*}{**Electrode**} & \multirow{2}{*}{**Case**} & \multicolumn{2}{c}{**Accuracy (\%)**} & \multicolumn{2}{c}{**Potential (\(\mu\)V)**} \\ \cline{3-6}  & & & \(\boldsymbol{T}\)**-Value** & \(\boldsymbol{p}\)**-Value** & \(\boldsymbol{T}\)**-Value** & \(\boldsymbol{p}\)**-Value** \\ \hline \multirow{4}{*}{N200} & T3 & & 2.335 & 0.028 & \(-\)0.1772 & 0.859 \\  & T4 & target & 3.366 & 0.002 * & \(-\)1.237 & 0.217 \\  & Fz & vs. & 6.915 & 0.000 *** & \(-\)3.971 & 0.000 *** \\  & Cz & non-target & 5.159 & 0.000 *** & \(-\)2.249 & 0.025 \\  & Pz & & 2.298 & 0.031 * & \(-\)0.576 & 0.565 \\ \hline \multirow{4}{*}{P300} & T3 & & 5.873 & 0.000 *** & 2.521 & 0.012 \\  & T4 & target & 5.113 & 0.000 *** & 1.021 & 0.308 \\  & Fz & vs. & 3.743 & 0.001 * & 0.028 & 0.977 \\  & Cz & non-target & 4.335 & 0.000 *** & 2.011 & 0.045 * \\  & Pz & & 4.663 & 0.000 *** & 2.792 & 0.005 * \\ \hline \multirow{4}{*}{N2P3} & T3 & & 7.935 & 0.000 *** & 4.288 & 0.000 *** \\  & T4 & target & 6.496 & 0.000 *** & 3.046 & 0.002 * \\ \cline{1-1}  & Fz & vs. & 11.327 & 0.000 *** & 4.224 & 0.000 *** \\ \cline{1-1}  & Cz & non-target & 9.182 & 0.000 *** & 4.522 & 0.000 *** \\ \cline{1-1}  & Pz & & 9.245 & 0.000 *** & 4.160 & 0.000 *** \\ \hline \hline \end{tabular}  
* \(p<0.05\);*** \(p<0.001\).  
\end{table}
Table 5: Paired samples \(t\)-test results of all trials between the target and non-target options regarding accuracy and potential.  
In addition, from the N2P3 results for online output (Table 4), the best-performing electrode Pz and the worst-performing electrode T3 were subjected to paired samples t-test. The mean between Pz and T3 did not reach a significant level (Table 6). So, we inferred that all five points are suitable for sampling electrode points.