Figure 3

Off-line comparison of the BCI performance of the 4-target and the 32-target speller. The dipicited box plots show the distribution of off-line accuries and ITRs across the 58 participants at different time windows. The boxes indicate the middle 50%, the lines that devide the boxes indicate the median, the antennas indicate the upper and lower quartile, and the individual points indicate outliers, i. e. data points outside 1.5 times the interquartile range.