condition mean min max ZT0-3 5.154715 4.637465000000001 5.671965 ZT4-7 3.566885 3.566885 3.566885 ZT8-11 4.490015 4.490015 4.490015 ZT12-15 0 0 0 ZT16-19 4.968145 4.968145 4.968145 ZT20-23 5.03679 5.03679 5.03679