condition mean min max ZT0-3 40.398004 40.398004 40.398004 ZT4-7 26.2541275 26.2541275 26.2541275 ZT8-11 23.691111999999997 23.691111999999997 23.691111999999997 ZT12-15 30.0342015 30.0342015 30.0342015 ZT16-19 55.0585325 55.0585325 55.0585325 ZT20-23 67.6741625 67.6741625 67.6741625