condition mean min max ZT0-3 9.399999999999999 9.399999999999999 9.399999999999999 ZT4-7 3.0 3.0 3.0 ZT8-11 47.2 47.2 47.2 ZT12-15 41.9 41.9 41.9 ZT16-19 4.5 4.5 4.5 ZT20-23 18.7 18.7 18.7