condition mean min max ZT0-3 12.149999999999999 12.149999999999999 12.149999999999999 ZT4-7 4.2 4.2 4.2 ZT8-11 9.3 9.3 9.3 ZT12-15 8.2 8.2 8.2 ZT16-19 13.95 13.95 13.95 ZT20-23 12.15 12.15 12.15