condition mean min max ZT0-3 4.454446666666667 3.020855 7.20949 ZT4-7 3.36984 3.36984 3.36984 ZT8-11 1.8401399999999999 1.8401399999999999 1.8401399999999999 ZT12-15 6.148885 5.91614 6.3816299999999995 ZT16-19 3.96553 3.96553 3.96553 ZT20-23 4.752575 4.752575 4.752575