condition mean min max ZT0-3 2.200072666666667 0.752678 3.22724 ZT4-7 1.196221 1.196221 1.196221 ZT8-11 2.45072 2.45072 2.45072 ZT12-15 4.221 2.968815 5.473185000000001 ZT16-19 4.10518 4.10518 4.10518 ZT20-23 6.1907499999999995 6.1907499999999995 6.1907499999999995