condition mean min max ZT0-3 8.037885 8.037885 8.037885 ZT4-7 5.46862 5.46862 5.46862 ZT8-11 2.29958 2.29958 2.29958 ZT12-15 4.75554 4.75554 4.75554 ZT16-19 3.1402650000000003 3.1402650000000003 3.1402650000000003 ZT20-23 5.579955 5.579955 5.579955