condition mean min max ZT0-3 20.756525 19.5837 21.92935 ZT4-7 24.51315 24.51315 24.51315 ZT8-11 23.82915 23.82915 23.82915 ZT12-15 0 0 0 ZT16-19 23.40475 23.40475 23.40475 ZT20-23 27.29465 27.29465 27.29465