condition mean min max ZT0-3 6.449235 6.449235 6.449235 ZT4-7 4.186405000000001 4.186405000000001 4.186405000000001 ZT8-11 10.3596 10.3596 10.3596 ZT12-15 7.807595000000001 7.807595000000001 7.807595000000001 ZT16-19 14.22705 14.22705 14.22705 ZT20-23 7.66996 7.66996 7.66996