condition mean min max ZT0-3 6.3946275 4.304795 8.48446 ZT4-7 2.30462 2.30462 2.30462 ZT8-11 2.82468 2.82468 2.82468 ZT12-15 0 0 0 ZT16-19 6.820105 6.820105 6.820105 ZT20-23 6.6091999999999995 6.6091999999999995 6.6091999999999995