condition mean min max ZT0-3 7.19165 7.19165 7.19165 ZT4-7 6.532855 6.532855 6.532855 ZT8-11 5.478535 5.478535 5.478535 ZT12-15 7.31859 7.31859 7.31859 ZT16-19 6.645110000000001 6.645110000000001 6.645110000000001 ZT20-23 6.4970300000000005 6.4970300000000005 6.4970300000000005