condition mean min max ZT0-3 2.734828333333333 1.621535 3.4244149999999998 ZT4-7 3.4853650000000003 3.4853650000000003 3.4853650000000003 ZT8-11 1.95335 1.95335 1.95335 ZT12-15 2.7877175000000003 2.68295 2.892485 ZT16-19 3.630205 3.630205 3.630205 ZT20-23 3.999655 3.999655 3.999655