condition mean min max ZT0-3 5.086315 5.086315 5.086315 ZT4-7 2.97198 2.97198 2.97198 ZT8-11 1.8701699999999999 1.8701699999999999 1.8701699999999999 ZT12-15 2.639785 2.639785 2.639785 ZT16-19 7.87044 7.87044 7.87044 ZT20-23 6.3439250000000005 6.3439250000000005 6.3439250000000005