condition mean min max ZT0-3 7.050000000000001 7.050000000000001 7.050000000000001 ZT4-7 6.5 6.5 6.5 ZT8-11 16.05 16.05 16.05 ZT12-15 6.199999999999999 6.199999999999999 6.199999999999999 ZT16-19 7.199999999999999 7.199999999999999 7.199999999999999 ZT20-23 33.05 33.05 33.05