condition mean min max ZT0-3 2.0495475 1.279945 2.81915 ZT4-7 3.7749949999999997 3.7749949999999997 3.7749949999999997 ZT8-11 5.3638200000000005 5.3638200000000005 5.3638200000000005 ZT12-15 0 0 0 ZT16-19 3.779395 3.779395 3.779395 ZT20-23 4.133570000000001 4.133570000000001 4.133570000000001