condition mean min max ZT0-3 3.988595 3.7164650000000004 4.260725 ZT4-7 8.415140000000001 8.415140000000001 8.415140000000001 ZT8-11 3.4643800000000002 3.4643800000000002 3.4643800000000002 ZT12-15 0 0 0 ZT16-19 4.76269 4.76269 4.76269 ZT20-23 9.73885 9.73885 9.73885