condition mean min max ZT0-3 18.652475 17.9542 19.350749999999998 ZT4-7 22.974449999999997 22.974449999999997 22.974449999999997 ZT8-11 27.016 27.016 27.016 ZT12-15 0 0 0 ZT16-19 23.700699999999998 23.700699999999998 23.700699999999998 ZT20-23 22.8871 22.8871 22.8871