condition mean min max ZT0-3 7.35907 7.35907 7.35907 ZT4-7 6.80993 6.80993 6.80993 ZT8-11 1.53406 1.53406 1.53406 ZT12-15 3.074345 3.074345 3.074345 ZT16-19 4.973345 4.973345 4.973345 ZT20-23 7.677215 7.677215 7.677215