condition mean min max ZT0-3 19.5066 17.739449999999998 21.27375 ZT4-7 13.6732 13.6732 13.6732 ZT8-11 13.1123 13.1123 13.1123 ZT12-15 0 0 0 ZT16-19 23.0191 23.0191 23.0191 ZT20-23 26.9973 26.9973 26.9973