condition mean min max ZT0-3 3.450515 1.67801 5.22302 ZT4-7 5.94425 5.94425 5.94425 ZT8-11 5.429220000000001 5.429220000000001 5.429220000000001 ZT12-15 0 0 0 ZT16-19 20.66155 20.66155 20.66155 ZT20-23 19.727600000000002 19.727600000000002 19.727600000000002