condition mean min max ZT0-3 3.6995750000000003 3.6995750000000003 3.6995750000000003 ZT4-7 2.67398 2.67398 2.67398 ZT8-11 3.1892050000000003 3.1892050000000003 3.1892050000000003 ZT12-15 5.2167 5.2167 5.2167 ZT16-19 6.3296 6.3296 6.3296 ZT20-23 4.430285 4.430285 4.430285