condition mean min max ZT0-3 6.185421666666667 5.865615 6.44318 ZT4-7 6.37279 6.37279 6.37279 ZT8-11 9.693805 9.693805 9.693805 ZT12-15 13.248265 8.73038 17.76615 ZT16-19 14.9983 14.9983 14.9983 ZT20-23 9.44196 9.44196 9.44196