condition mean min max ZT0-3 4.760149999999999 4.760149999999999 4.760149999999999 ZT4-7 3.397495 3.397495 3.397495 ZT8-11 3.879605 3.879605 3.879605 ZT12-15 5.053140000000001 5.053140000000001 5.053140000000001 ZT16-19 6.19247 6.19247 6.19247 ZT20-23 5.68461 5.68461 5.68461