condition mean min max ZT0-3 209.692735 209.692735 209.692735 ZT4-7 168.927216 168.927216 168.927216 ZT8-11 206.5549575 206.5549575 206.5549575 ZT12-15 226.01651750000002 226.01651750000002 226.01651750000002 ZT16-19 253.23760149999998 253.23760149999998 253.23760149999998 ZT20-23 216.1024375 216.1024375 216.1024375