condition mean min max ZT0-3 5.696935 5.696935 5.696935 ZT4-7 3.711365 3.711365 3.711365 ZT8-11 3.725955 3.725955 3.725955 ZT12-15 4.298500000000001 4.298500000000001 4.298500000000001 ZT16-19 6.3223400000000005 6.3223400000000005 6.3223400000000005 ZT20-23 6.115489999999999 6.115489999999999 6.115489999999999