condition mean min max ZT0-3 7.914665 7.643425000000001 8.185905 ZT4-7 3.3767050000000003 3.3767050000000003 3.3767050000000003 ZT8-11 5.93599 5.93599 5.93599 ZT12-15 0 0 0 ZT16-19 6.40923 6.40923 6.40923 ZT20-23 6.13524 6.13524 6.13524