Activity strength of L dwarfs as a function of spectral type. Top panel: activity strength detections (black circles) and upper limits (gray arrows), as reported in Table 6, are both shown. Bottom panel: activity strength of Hα detections only (smaller black circles), with half spectral types rounded down. For each spectral type bin (L4 and L5 are treated as a single bin) the full range of detections (light gray bar), the inter-quartile range (medium gray bar), and the median (larger dark gray circle) are shown, corresponding to the values shown in Figure 6 and used in Section 7. In both panels, the values corresponding to the SDSS Hα detection limit of EW ﹩\geqslant \;0.75﹩ Å are shown (red dashed line).