condition mean min max ZT0-3 17.383229 17.383229 17.383229 ZT4-7 18.141163499999998 18.141163499999998 18.141163499999998 ZT8-11 18.329916 18.329916 18.329916 ZT12-15 17.503688500000003 17.503688500000003 17.503688500000003 ZT16-19 18.0888555 18.0888555 18.0888555 ZT20-23 18.2343185 18.2343185 18.2343185