condition mean min max ZT0-3 10.12935 10.12935 10.12935 ZT4-7 6.188935 6.188935 6.188935 ZT8-11 7.9842200000000005 7.9842200000000005 7.9842200000000005 ZT12-15 11.475000000000001 11.475000000000001 11.475000000000001 ZT16-19 14.4356 14.4356 14.4356 ZT20-23 14.622933333333334 14.622933333333334 14.622933333333334