condition mean min max ZT0-3 9.315275 7.51985 11.110700000000001 ZT4-7 5.450715000000001 5.450715000000001 5.450715000000001 ZT8-11 6.1612849999999995 6.1612849999999995 6.1612849999999995 ZT12-15 0 0 0 ZT16-19 8.053505000000001 8.053505000000001 8.053505000000001 ZT20-23 8.374189999999999 8.374189999999999 8.374189999999999