condition mean min max ZT0-3 4.859255 3.7503450000000003 5.968165 ZT4-7 7.520849999999999 7.520849999999999 7.520849999999999 ZT8-11 2.79733 2.79733 2.79733 ZT12-15 0 0 0 ZT16-19 9.736235 9.736235 9.736235 ZT20-23 19.73055 19.73055 19.73055