condition mean min max ZT0-3 18.112676 18.112676 18.112676 ZT4-7 14.202091500000002 14.202091500000002 14.202091500000002 ZT8-11 15.213908 15.213908 15.213908 ZT12-15 15.965496000000002 15.965496000000002 15.965496000000002 ZT16-19 14.666295000000002 14.666295000000002 14.666295000000002 ZT20-23 17.278863 17.278863 17.278863