condition mean min max ZT0-3 221.564278 221.564278 221.564278 ZT4-7 344.1582595 344.1582595 344.1582595 ZT8-11 356.681875 356.681875 356.681875 ZT12-15 300.1239825 300.1239825 300.1239825 ZT16-19 237.0429245 237.0429245 237.0429245 ZT20-23 208.0874965 208.0874965 208.0874965