2.7 Determining Signal-to-Noise Ratios at the Single Trial Level
The signal-to-noise ratios were calculated for each component in the STP, STW, and Averaged ERP approaches in order to determine if the SNR for the STP approach would be similar to the other approaches. Given that the baseline period is not a flat line in single trials and rarely so even in averaged ERPs, “noise” was calculated by obtaining the standard deviation of the amplitude of all data points in the baseline period (i.e., -200 ms to 0 ms). The “signal” was the peak amplitude of each component. This procedure is similar to the approach for determining a SNR value for components in averaged ERPs (Debener, Ullsperger, Siegel, & Engel, 2006; Hu et al., 2010; Spencer, 2005).