condition mean min max ZT0-3 60.259048 60.259048 60.259048 ZT4-7 64.9711035 64.9711035 64.9711035 ZT8-11 63.390020500000006 63.390020500000006 63.390020500000006 ZT12-15 58.481511499999996 58.481511499999996 58.481511499999996 ZT16-19 40.6214425 40.6214425 40.6214425 ZT20-23 33.679749 33.679749 33.679749