condition mean min max ZT0-3 6.419595 6.419595 6.419595 ZT4-7 7.521135 7.521135 7.521135 ZT8-11 5.970269999999999 5.970269999999999 5.970269999999999 ZT12-15 5.6488499999999995 5.6488499999999995 5.6488499999999995 ZT16-19 5.828105000000001 5.828105000000001 5.828105000000001 ZT20-23 5.086945 5.086945 5.086945