condition mean min max ZT0-3 9.138912 9.138912 9.138912 ZT4-7 8.109413499999999 8.109413499999999 8.109413499999999 ZT8-11 9.5233165 9.5233165 9.5233165 ZT12-15 8.784091 8.784091 8.784091 ZT16-19 10.208471500000002 10.208471500000002 10.208471500000002 ZT20-23 10.03971 10.03971 10.03971