condition mean min max ZT0-3 2.323905 1.05254 3.59527 ZT4-7 3.9898 3.9898 3.9898 ZT8-11 1.4418 1.4418 1.4418 ZT12-15 0 0 0 ZT16-19 2.8245750000000003 2.8245750000000003 2.8245750000000003 ZT20-23 1.7715315 1.7715315 1.7715315