condition mean min max ZT0-3 11.471785 11.471785 11.471785 ZT4-7 14.2100775 14.2100775 14.2100775 ZT8-11 17.0120405 17.0120405 17.0120405 ZT12-15 18.1760065 18.1760065 18.1760065 ZT16-19 17.708053 17.708053 17.708053 ZT20-23 21.438416 21.438416 21.438416