condition mean min max ZT0-3 4.001695 4.001695 4.001695 ZT4-7 3.442425 3.442425 3.442425 ZT8-11 2.867155 2.867155 2.867155 ZT12-15 4.016115 4.016115 4.016115 ZT16-19 4.7588349999999995 4.7588349999999995 4.7588349999999995 ZT20-23 4.14236 4.14236 4.14236