condition mean min max ZT0-3 8.382279 8.382279 8.382279 ZT4-7 8.481989500000001 8.481989500000001 8.481989500000001 ZT8-11 8.5665655 8.5665655 8.5665655 ZT12-15 8.9736265 8.9736265 8.9736265 ZT16-19 9.877561 9.877561 9.877561 ZT20-23 8.91737 8.91737 8.91737