condition mean min max ZT0-3 0.495353 0.477688 0.513018 ZT4-7 0.7001425 0.7001425 0.7001425 ZT8-11 2.357245 2.357245 2.357245 ZT12-15 0 0 0 ZT16-19 1.77806 1.77806 1.77806 ZT20-23 1.17346 1.17346 1.17346