condition mean min max ZT0-3 15.387485 15.387485 15.387485 ZT4-7 16.489586000000003 16.489586000000003 16.489586000000003 ZT8-11 13.315353 13.315353 13.315353 ZT12-15 15.430822500000001 15.430822500000001 15.430822500000001 ZT16-19 14.192671 14.192671 14.192671 ZT20-23 14.8400645 14.8400645 14.8400645