condition mean min max ZT0-3 2.543655 2.543655 2.543655 ZT4-7 2.10688 2.10688 2.10688 ZT8-11 2.5195350000000003 2.5195350000000003 2.5195350000000003 ZT12-15 3.7556249999999998 3.7556249999999998 3.7556249999999998 ZT16-19 4.418570000000001 4.418570000000001 4.418570000000001 ZT20-23 5.28371 5.28371 5.28371