condition mean min max ZT0-3 2.13515 2.13515 2.13515 ZT4-7 1.4752049999999999 1.4752049999999999 1.4752049999999999 ZT8-11 1.4936500000000001 1.4936500000000001 1.4936500000000001 ZT12-15 1.273175 1.273175 1.273175 ZT16-19 1.987765 1.987765 1.987765 ZT20-23 1.9708999999999999 1.9708999999999999 1.9708999999999999