condition mean min max ZT0-3 8.21571 8.052645 8.451920000000001 ZT4-7 5.680820000000001 5.680820000000001 5.680820000000001 ZT8-11 3.7733499999999998 3.7733499999999998 3.7733499999999998 ZT12-15 3.30438 3.1397700000000004 3.46899 ZT16-19 4.252175 4.252175 4.252175 ZT20-23 5.90307 5.90307 5.90307