condition mean min max ZT0-3 7.218181666666666 6.683145 7.638145 ZT4-7 6.55227 6.55227 6.55227 ZT8-11 10.047135 10.047135 10.047135 ZT12-15 14.726375 13.83695 15.6158 ZT16-19 11.556999999999999 11.556999999999999 11.556999999999999 ZT20-23 9.66129 9.66129 9.66129