condition mean min max ZT0-3 6.7068900000000005 6.067745 7.973409999999999 ZT4-7 3.98458 3.98458 3.98458 ZT8-11 4.09483 4.09483 4.09483 ZT12-15 6.639335 5.571875 7.706795 ZT16-19 6.283485000000001 6.283485000000001 6.283485000000001 ZT20-23 3.402835 3.402835 3.402835