condition mean min max ZT0-3 6.92973 6.92973 6.92973 ZT4-7 7.8545855 7.8545855 7.8545855 ZT8-11 7.262587 7.262587 7.262587 ZT12-15 7.609374 7.609374 7.609374 ZT16-19 7.1422475 7.1422475 7.1422475 ZT20-23 7.54972 7.54972 7.54972