condition mean min max ZT0-3 6.93247 6.93247 6.93247 ZT4-7 4.08671 4.08671 4.08671 ZT8-11 5.49375 5.49375 5.49375 ZT12-15 6.4117049999999995 6.4117049999999995 6.4117049999999995 ZT16-19 8.57648 8.57648 8.57648 ZT20-23 7.536135 7.536135 7.536135