condition mean min max ZT0-3 7.731805 7.731805 7.731805 ZT4-7 5.077935 5.077935 5.077935 ZT8-11 9.399495 9.399495 9.399495 ZT12-15 8.176445000000001 8.176445000000001 8.176445000000001 ZT16-19 13.986699999999999 13.986699999999999 13.986699999999999 ZT20-23 9.401060000000001 9.401060000000001 9.401060000000001