condition mean min max ZT0-3 3.8503333333333334 3.31506 4.118975 ZT4-7 3.14546 3.14546 3.14546 ZT8-11 3.43803 3.43803 3.43803 ZT12-15 8.404145 7.122120000000001 9.68617 ZT16-19 9.530875 9.530875 9.530875 ZT20-23 7.136375 7.136375 7.136375