condition mean min max ZT0-3 18.789099999999998 17.59535 19.98285 ZT4-7 7.540445 7.540445 7.540445 ZT8-11 8.70787 8.70787 8.70787 ZT12-15 0 0 0 ZT16-19 12.897549999999999 12.897549999999999 12.897549999999999 ZT20-23 11.9981 11.9981 11.9981