condition mean min max ZT0-3 6.6911425 6.15751 7.224775 ZT4-7 4.5802700000000005 4.5802700000000005 4.5802700000000005 ZT8-11 15.17115 15.17115 15.17115 ZT12-15 0 0 0 ZT16-19 13.6701 13.6701 13.6701 ZT20-23 9.832995 9.832995 9.832995