condition mean min max ZT0-3 0.8410806666666667 0.6320245 1.17319 ZT4-7 1.247595 1.247595 1.247595 ZT8-11 1.708534 1.708534 1.708534 ZT12-15 2.612405 2.273985 2.950825 ZT16-19 2.32813 2.32813 2.32813 ZT20-23 1.531685 1.531685 1.531685