condition mean min max ZT0-3 9.023453333333334 4.268185 12.1597 ZT4-7 2.852545 2.852545 2.852545 ZT8-11 3.90279 3.90279 3.90279 ZT12-15 8.456615 7.38658 9.52665 ZT16-19 9.71673 9.71673 9.71673 ZT20-23 13.57665 13.57665 13.57665