condition mean min max ZT0-3 19.022746 19.022746 19.022746 ZT4-7 20.1393115 20.1393115 20.1393115 ZT8-11 25.592284499999998 25.592284499999998 25.592284499999998 ZT12-15 23.6212625 23.6212625 23.6212625 ZT16-19 19.002649 19.002649 19.002649 ZT20-23 21.880948 21.880948 21.880948