condition mean min max ZT0-3 13.559578333333333 9.851135 15.72 ZT4-7 7.673995 7.673995 7.673995 ZT8-11 9.681915 9.681915 9.681915 ZT12-15 23.319525 21.81745 24.8216 ZT16-19 25.0026 25.0026 25.0026 ZT20-23 20.909100000000002 20.909100000000002 20.909100000000002