condition mean min max ZT0-3 8.952795 6.749305 11.156285 ZT4-7 15.15225 15.15225 15.15225 ZT8-11 23.808750000000003 23.808750000000003 23.808750000000003 ZT12-15 0 0 0 ZT16-19 61.561550000000004 61.561550000000004 61.561550000000004 ZT20-23 76.80075 76.80075 76.80075