condition mean min max ZT0-3 0.5448835 0.368937 0.72083 ZT4-7 0.3637515 0.3637515 0.3637515 ZT8-11 0.730015 0.730015 0.730015 ZT12-15 0 0 0 ZT16-19 1.452235 1.452235 1.452235 ZT20-23 1.4626169999999998 1.4626169999999998 1.4626169999999998