condition mean min max ZT0-3 6.482335 6.32164 6.6430299999999995 ZT4-7 5.05919 5.05919 5.05919 ZT8-11 4.231975 4.231975 4.231975 ZT12-15 0 0 0 ZT16-19 6.114145000000001 6.114145000000001 6.114145000000001 ZT20-23 6.1008700000000005 6.1008700000000005 6.1008700000000005