condition mean min max ZT0-3 7.7 7.7 7.7 ZT4-7 15.6 15.6 15.6 ZT8-11 54.599999999999994 54.599999999999994 54.599999999999994 ZT12-15 35.650000000000006 35.650000000000006 35.650000000000006 ZT16-19 62.35 62.35 62.35 ZT20-23 9.7 9.7 9.7