condition mean min max ZT0-3 451.317672 451.317672 451.317672 ZT4-7 439.430828 439.430828 439.430828 ZT8-11 406.4525595 406.4525595 406.4525595 ZT12-15 489.57023000000004 489.57023000000004 489.57023000000004 ZT16-19 466.699073 466.699073 466.699073 ZT20-23 518.8101485 518.8101485 518.8101485