condition mean min max ZT0-3 6.3 6.3 6.3 ZT4-7 23.1 23.1 23.1 ZT8-11 2.5 2.5 2.5 ZT12-15 1.2999999999999998 1.2999999999999998 1.2999999999999998 ZT16-19 11.149999999999999 11.149999999999999 11.149999999999999 ZT20-23 15.3 15.3 15.3