condition mean min max ZT0-3 7.554375 7.554375 7.554375 ZT4-7 4.311825 4.311825 4.311825 ZT8-11 4.59748 4.59748 4.59748 ZT12-15 6.46316 6.46316 6.46316 ZT16-19 7.586499999999999 7.586499999999999 7.586499999999999 ZT20-23 6.8527249999999995 6.8527249999999995 6.8527249999999995