condition mean min max ZT0-3 13.4239725 12.487945 14.36 ZT4-7 31.10575 31.10575 31.10575 ZT8-11 50.04445 50.04445 50.04445 ZT12-15 0 0 0 ZT16-19 20.4614 20.4614 20.4614 ZT20-23 8.22903 8.22903 8.22903