condition mean min max ZT0-3 5.0 5.0 5.0 ZT4-7 6.2 6.2 6.2 ZT8-11 5.050000000000001 5.050000000000001 5.050000000000001 ZT12-15 13.200000000000001 13.200000000000001 13.200000000000001 ZT16-19 9.350000000000001 9.350000000000001 9.350000000000001 ZT20-23 16.55 16.55 16.55