condition mean min max ZT0-3 9.006661 9.006661 9.006661 ZT4-7 10.0874395 10.0874395 10.0874395 ZT8-11 8.5403155 8.5403155 8.5403155 ZT12-15 8.6104165 8.6104165 8.6104165 ZT16-19 8.1711585 8.1711585 8.1711585 ZT20-23 9.615831 9.615831 9.615831