condition mean min max ZT0-3 2.354815 2.354815 2.354815 ZT4-7 2.8434850000000003 2.8434850000000003 2.8434850000000003 ZT8-11 2.04792 2.04792 2.04792 ZT12-15 1.6779199999999999 1.6779199999999999 1.6779199999999999 ZT16-19 2.7605250000000003 2.7605250000000003 2.7605250000000003 ZT20-23 3.13139 3.13139 3.13139