condition mean min max ZT0-3 12.399999999999999 12.399999999999999 12.399999999999999 ZT4-7 5.9 5.9 5.9 ZT8-11 15.0 15.0 15.0 ZT12-15 26.25 26.25 26.25 ZT16-19 23.5 23.5 23.5 ZT20-23 25.3 25.3 25.3