condition mean min max ZT0-3 17.353933333333334 17.353933333333334 17.353933333333334 ZT4-7 26.0264 26.0264 26.0264 ZT8-11 7.008315 7.008315 7.008315 ZT12-15 3.0150949999999996 3.0150949999999996 3.0150949999999996 ZT16-19 9.34407 9.34407 9.34407 ZT20-23 15.6064 15.6064 15.6064