condition mean min max ZT0-3 1.9077700000000002 1.8670200000000001 1.9485200000000003 ZT4-7 3.657575 3.657575 3.657575 ZT8-11 4.0193200000000004 4.0193200000000004 4.0193200000000004 ZT12-15 0 0 0 ZT16-19 2.9152649999999998 2.9152649999999998 2.9152649999999998 ZT20-23 2.329255 2.329255 2.329255