condition mean min max ZT0-3 1.2 1.2 1.2 ZT4-7 6.4 6.4 6.4 ZT8-11 0.8 0.8 0.8 ZT12-15 7.8999999999999995 7.8999999999999995 7.8999999999999995 ZT16-19 10.399999999999999 10.399999999999999 10.399999999999999 ZT20-23 7.3 7.3 7.3