condition mean min max ZT0-3 2.834835 2.834835 2.834835 ZT4-7 2.146555 2.146555 2.146555 ZT8-11 3.7059800000000003 3.7059800000000003 3.7059800000000003 ZT12-15 3.684485 3.684485 3.684485 ZT16-19 3.33893 3.33893 3.33893 ZT20-23 2.83999 2.83999 2.83999