condition mean min max ZT0-3 12.4304752925 10.04401915 14.816931435 ZT4-7 8.62099615175 7.9133259215 9.328666382 ZT8-11 7.772277203 7.162367217 8.382187189 ZT12-15 9.55251026025 9.1590473925 9.945973128 ZT16-19 12.4969098125 12.156376885 12.83744274 ZT20-23 17.67457155 15.95080058 19.39834252