condition mean min max ZT0-3 7.3272224999999995 7.2469 7.407545 ZT4-7 7.264005 7.264005 7.264005 ZT8-11 13.59855 13.59855 13.59855 ZT12-15 0 0 0 ZT16-19 9.63876 9.63876 9.63876 ZT20-23 6.886545 6.886545 6.886545