condition mean min max ZT0-3 14.513713 14.513713 14.513713 ZT4-7 11.8466275 11.8466275 11.8466275 ZT8-11 12.425678000000001 12.425678000000001 12.425678000000001 ZT12-15 13.6197575 13.6197575 13.6197575 ZT16-19 12.6270105 12.6270105 12.6270105 ZT20-23 14.528162 14.528162 14.528162