condition mean min max ZT0-3 2.6058733333333333 2.368505 2.9609050000000003 ZT4-7 4.123895 4.123895 4.123895 ZT8-11 5.039985 5.039985 5.039985 ZT12-15 8.218885 7.7696000000000005 8.66817 ZT16-19 7.50722 7.50722 7.50722 ZT20-23 4.549045 4.549045 4.549045