condition mean min max ZT0-3 8.962243333333333 7.674395 11.469249999999999 ZT4-7 14.248750000000001 14.248750000000001 14.248750000000001 ZT8-11 13.1318 13.1318 13.1318 ZT12-15 9.5661725 8.99162 10.140725 ZT16-19 7.78373 7.78373 7.78373 ZT20-23 6.896985 6.896985 6.896985