condition mean min max ZT0-3 15.14595 15.14595 15.14595 ZT4-7 9.179895 9.179895 9.179895 ZT8-11 6.88035 6.88035 6.88035 ZT12-15 8.001845 8.001845 8.001845 ZT16-19 15.313500000000001 15.313500000000001 15.313500000000001 ZT20-23 13.52745 13.52745 13.52745