condition mean min max ZT0-3 3.9989950000000003 3.2334750000000003 4.764515 ZT4-7 3.368755 3.368755 3.368755 ZT8-11 6.777835 6.777835 6.777835 ZT12-15 0 0 0 ZT16-19 7.70986 7.70986 7.70986 ZT20-23 8.00434 8.00434 8.00434