condition mean min max ZT0-3 3.9857 3.9857 3.9857 ZT4-7 1.9775325000000001 1.9775325000000001 1.9775325000000001 ZT8-11 3.3395349999999997 3.3395349999999997 3.3395349999999997 ZT12-15 7.723 7.723 7.723 ZT16-19 6.5895150000000005 6.5895150000000005 6.5895150000000005 ZT20-23 4.989975 4.989975 4.989975