condition mean min max ZT0-3 4.565763333333333 2.97228 5.93299 ZT4-7 3.3107300000000004 3.3107300000000004 3.3107300000000004 ZT8-11 3.4782650000000004 3.4782650000000004 3.4782650000000004 ZT12-15 4.16109 3.683755 4.638425 ZT16-19 3.1850199999999997 3.1850199999999997 3.1850199999999997 ZT20-23 5.28276 5.28276 5.28276