condition mean min max ZT0-3 6.19856 3.29293 8.99348 ZT4-7 1.162905 1.162905 1.162905 ZT8-11 1.241515 1.241515 1.241515 ZT12-15 3.74463 3.6079 3.88136 ZT16-19 4.293805 4.293805 4.293805 ZT20-23 7.9022 7.9022 7.9022