condition mean min max ZT0-3 0.382288965 0.107431144 0.657146786 ZT4-7 4.246088402 3.3533017245 5.1388750795 ZT8-11 6.1786096575 6.1137475565 6.2434717585 ZT12-15 9.902380754 8.365073403 11.439688105 ZT16-19 14.64750222 11.517732345 17.777272095 ZT20-23 36.864740775 25.72245246 48.00702909