condition mean min max ZT0-3 17.24035 16.498350000000002 17.98235 ZT4-7 16.8136 16.8136 16.8136 ZT8-11 19.07575 19.07575 19.07575 ZT12-15 0 0 0 ZT16-19 25.629849999999998 25.629849999999998 25.629849999999998 ZT20-23 20.62475 20.62475 20.62475