condition mean min max ZT0-3 4.3968766666666665 3.926805 4.92599 ZT4-7 4.40937 4.40937 4.40937 ZT8-11 2.62065 2.62065 2.62065 ZT12-15 3.5598725 2.965545 4.1542 ZT16-19 3.11365 3.11365 3.11365 ZT20-23 4.262555 4.262555 4.262555