condition mean min max ZT0-3 24.558766666666667 16.7517 30.777549999999998 ZT4-7 9.729405 9.729405 9.729405 ZT8-11 8.434635 8.434635 8.434635 ZT12-15 6.37499 6.258345 6.4916350000000005 ZT16-19 8.685175000000001 8.685175000000001 8.685175000000001 ZT20-23 17.5987 17.5987 17.5987