condition mean min max ZT0-3 6.411925 4.72344 8.365295 ZT4-7 4.889835 4.889835 4.889835 ZT8-11 2.0144 2.0144 2.0144 ZT12-15 2.9395525 2.4504200000000003 3.4286849999999998 ZT16-19 1.2644375 1.2644375 1.2644375 ZT20-23 2.892525 2.892525 2.892525