condition mean min max ZT0-3 22.525623 22.525623 22.525623 ZT4-7 19.9975275 19.9975275 19.9975275 ZT8-11 20.1990455 20.1990455 20.1990455 ZT12-15 21.641821999999998 21.641821999999998 21.641821999999998 ZT16-19 19.031292 19.031292 19.031292 ZT20-23 20.138928 20.138928 20.138928