condition mean min max ZT0-3 14.909726666666668 6.486745 27.15915 ZT4-7 6.971439999999999 6.971439999999999 6.971439999999999 ZT8-11 4.273759999999999 4.273759999999999 4.273759999999999 ZT12-15 9.577972500000001 8.179995 10.975950000000001 ZT16-19 8.012224999999999 8.012224999999999 8.012224999999999 ZT20-23 8.03313 8.03313 8.03313