condition mean min max ZT0-3 2.4108383333333334 1.63132 3.1922300000000003 ZT4-7 4.625025000000001 4.625025000000001 4.625025000000001 ZT8-11 17.26585 17.26585 17.26585 ZT12-15 9.098075 8.881 9.31515 ZT16-19 7.76886 7.76886 7.76886 ZT20-23 6.46823 6.46823 6.46823