condition mean min max ZT0-3 3.947265 1.94211 5.2783750000000005 ZT4-7 1.26323 1.26323 1.26323 ZT8-11 2.894375 2.894375 2.894375 ZT12-15 8.74676 8.314425 9.179095 ZT16-19 7.779095 7.779095 7.779095 ZT20-23 8.819685 8.819685 8.819685