condition mean min max ZT0-3 5.44009 4.91936 5.96082 ZT4-7 3.191175 3.191175 3.191175 ZT8-11 4.17832 4.17832 4.17832 ZT12-15 0 0 0 ZT16-19 6.68122 6.68122 6.68122 ZT20-23 7.25753 7.25753 7.25753