condition mean min max ZT0-3 3.372525 3.372525 3.372525 ZT4-7 2.23272 2.23272 2.23272 ZT8-11 4.385515 4.385515 4.385515 ZT12-15 3.7181699999999998 3.7181699999999998 3.7181699999999998 ZT16-19 3.5912949999999997 3.5912949999999997 3.5912949999999997 ZT20-23 4.4042 4.4042 4.4042