condition mean min max ZT0-3 7.977936666666667 5.366595 9.384170000000001 ZT4-7 6.25626 6.25626 6.25626 ZT8-11 7.2204 7.2204 7.2204 ZT12-15 7.53279 7.2481 7.81748 ZT16-19 7.31747 7.31747 7.31747 ZT20-23 10.475249999999999 10.475249999999999 10.475249999999999