condition mean min max ZT0-3 11.881499999999999 11.881499999999999 11.881499999999999 ZT4-7 11.325050000000001 11.325050000000001 11.325050000000001 ZT8-11 8.927265 8.927265 8.927265 ZT12-15 9.709 9.709 9.709 ZT16-19 12.87145 12.87145 12.87145 ZT20-23 14.49235 14.49235 14.49235