condition mean min max ZT0-3 21.556969 21.556969 21.556969 ZT4-7 16.096362 16.096362 16.096362 ZT8-11 20.9605945 20.9605945 20.9605945 ZT12-15 19.186334000000002 19.186334000000002 19.186334000000002 ZT16-19 22.4471245 22.4471245 22.4471245 ZT20-23 25.7173865 25.7173865 25.7173865