condition mean min max ZT0-3 9.590655 8.623425000000001 10.557884999999999 ZT4-7 7.238815000000001 7.238815000000001 7.238815000000001 ZT8-11 12.636050000000001 12.636050000000001 12.636050000000001 ZT12-15 0 0 0 ZT16-19 18.858449999999998 18.858449999999998 18.858449999999998 ZT20-23 12.568349999999999 12.568349999999999 12.568349999999999