condition mean min max ZT0-3 15.905325000000001 14.53965 17.271 ZT4-7 15.35455 15.35455 15.35455 ZT8-11 12.039855 12.039855 12.039855 ZT12-15 0 0 0 ZT16-19 19.9929 19.9929 19.9929 ZT20-23 21.628149999999998 21.628149999999998 21.628149999999998