condition mean min max ZT0-3 5.515525 5.515525 5.515525 ZT4-7 3.19551 3.19551 3.19551 ZT8-11 2.759785 2.759785 2.759785 ZT12-15 4.46836 4.46836 4.46836 ZT16-19 7.43068 7.43068 7.43068 ZT20-23 5.107105000000001 5.107105000000001 5.107105000000001