condition mean min max ZT0-3 8.605562 8.605562 8.605562 ZT4-7 10.2842935 10.2842935 10.2842935 ZT8-11 8.585595999999999 8.585595999999999 8.585595999999999 ZT12-15 7.850341 7.850341 7.850341 ZT16-19 8.037512 8.037512 8.037512 ZT20-23 8.7736105 8.7736105 8.7736105