condition mean min max ZT0-3 131.177507 131.177507 131.177507 ZT4-7 175.35096 175.35096 175.35096 ZT8-11 159.780927 159.780927 159.780927 ZT12-15 175.918714 175.918714 175.918714 ZT16-19 181.730662 181.730662 181.730662 ZT20-23 169.0541895 169.0541895 169.0541895