condition mean min max ZT0-3 8.266985 6.87294 9.542955 ZT4-7 2.59771 2.59771 2.59771 ZT8-11 1.17929 1.17929 1.17929 ZT12-15 6.9920775 4.681595 9.30256 ZT16-19 2.68356 2.68356 2.68356 ZT20-23 4.97279 4.97279 4.97279