condition mean min max ZT0-3 1.5757341666666667 0.7443525 2.10989 ZT4-7 1.035476 1.035476 1.035476 ZT8-11 2.55103 2.55103 2.55103 ZT12-15 1.8976325 1.8802750000000001 1.91499 ZT16-19 1.775575 1.775575 1.775575 ZT20-23 2.76855 2.76855 2.76855