condition mean min max ZT0-3 3.946725 3.946725 3.946725 ZT4-7 2.29521 2.29521 2.29521 ZT8-11 3.47994 3.47994 3.47994 ZT12-15 3.8186750000000003 3.8186750000000003 3.8186750000000003 ZT16-19 5.23758 5.23758 5.23758 ZT20-23 4.551525 4.551525 4.551525