condition mean min max ZT0-3 3.2446450000000002 3.2446450000000002 3.2446450000000002 ZT4-7 3.2539550000000004 3.2539550000000004 3.2539550000000004 ZT8-11 4.410985 4.410985 4.410985 ZT12-15 4.935455 4.935455 4.935455 ZT16-19 7.00486 7.00486 7.00486 ZT20-23 3.1754350000000002 3.1754350000000002 3.1754350000000002