condition mean min max ZT0-3 3.830445 3.0472099999999998 5.01768 ZT4-7 4.1724250000000005 4.1724250000000005 4.1724250000000005 ZT8-11 6.432589999999999 6.432589999999999 6.432589999999999 ZT12-15 8.2747575 8.141955 8.40756 ZT16-19 7.55799 7.55799 7.55799 ZT20-23 7.5442350000000005 7.5442350000000005 7.5442350000000005