condition mean min max ZT0-3 18.097093 18.097093 18.097093 ZT4-7 19.916936 19.916936 19.916936 ZT8-11 20.8070855 20.8070855 20.8070855 ZT12-15 16.2532765 16.2532765 16.2532765 ZT16-19 19.8648775 19.8648775 19.8648775 ZT20-23 21.116795500000002 21.116795500000002 21.116795500000002